Following is the C program for strncpy() function , When the above program is executed, it produces the following result . strcpy implementation in c. Home / Codes / c-1. Printf and scanf takes multiple arguments and these functions are called variable length arguments function or vararg function. src: It is a pointer to the source string which will be copied. So the last assignment of (dest[i] = source[i]) returns '\0'? ins.dataset.adChannel = cid; Which to me, it will break when trying to assign \0 from source to dest. window.ezoSTPixelAdd(slotId, 'adsensetype', 1); The strcpy function doesn't create a string (character array), it only copies a string (character array). Your parameters could (should) be better named, e.g. Lets see an example to understand the concept. Struct in C++ incorrect reading from file. @Assignments evaluate to the value assigned. How do i copy a string that has been dynamically allocated to another string that has been dynamically allocated? Stack Overflow for Teams is moving to its own domain! That's what you have to do if you want to fully emulate the original strcpy. strcmp is another string library function which is used to compare two strings and returns zero if both strings are same , returns +ve value if first string is greater than second string and returns -ve value if second string is greater than first string. I don't think that concept exists, in C. What if the size of dest is unknown in the function strcpy? strcpy Syntax: #include <cstring> char *strcpy ( char *to, const char *from ); The strcpy function copies characters in the string from to the string to, including the null termination. See also Manual Reference Pages - Strn (3) (e.g. n: The first n character copied from src to dest. Description. 2. If you translate it into another language and would like to be listed here, just let me know. @Assignments evaluate to the value assigned. char* strcpy (char* restrict destination, const char* restrict source); The strcpy () function copies the null-terminated C-string pointed to by source to the memory pointed to by destination. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. You can see printing Aticl with some garbage because no trailing null character is available. src: string which will be copied. The C strncpy function is a String Function, which is used to copy n number of characters from one string to another. The statement in line 20, appends a null character (\0) to the string. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If yes then please describe the scenario. You could perhaps write it more elegantly as a for loop: In custom_strncat you don't handle the condition where n > strlen(t). @simonc - your comment would be a correct answer, Just a note: In your example, you store the beginning of the. Connect and share knowledge within a single location that is structured and easy to search. We make use of First and third party cookies to improve our user experience. strcpy c implementation. It does not affect the source string. Following is the declaration for an array , For example char string[50]; string of length 50 characters. Stack Overflow for Teams is moving to its own domain! When the last char \0 will pass and copy while receive 0 and stop. Note that strcpy2() does the assignment (the copying) first, then the comparison. 5. modify it under the terms of the GNU Lesser General Public. ins.style.width = '100%'; This function is used for copying n characters of source string into destination string. Interview Questions On bitwise Operators C, Interview Questions On Memory Allocation C, Machine Learning, Data Science and Deep Learning, Statistics for Data Science, Data and Business Analysis, C Program to find the Range of Fundamental Data Types, Use of assert macro in C/C++ with Examples, What is strncpy_s and how to use strncpy_s in C, Implementation of memcpy in c language - AticleWorld, Function in C: Types, Advantages and Use - AticleWorld, What is difference between memmove and memcpy (memmove vs memcpy)? Guest Article If the length of the C string in source is less than num, only the content up to the terminating null-character is copied. What would be the correct option, copying \0 or not? cannot install flutter_plugins_tools, dependency error, How to make a transparent/wallpaper-showing Flutter app. Copying the null terminator is correct. Translations are freely permitted as long as they are released under the GNU Free Documentation License. The first if-statement checks if there is enough space in the s buffer to store the contents of t. The while loop will run until n reaches the value 0. Below program explains different usages of this library function: This article is contributed by Harsh Agarwal. strncpy, strncpy_s. Negative value <= The first character that does not match has a lower value in s1 than in s2. strcpy how to c using strcpy with int in c should i use strcpy in c strcpy and uart c which inclde c strcpy strcpy in c source code strcpy use in c strcpy and strncpy syntax in c strcpy c library how does strcpy work in c recreate strcpy in c strcpy c char* strcpy in c in funciont implement strcpy in c strcpy function user made in c strcpy . It is also used for extracting substrings. If the source string is shorter than n characters (number of characters want to copy), then the destination array is padded with zeros until a total of n characters have been written to it. If the length of the C string in source is less than num, only the content up to the terminating null-character is copied.. n is the maximum number of characters in source you you want to copy, and bfsize doesn't exist in the . _____1. It returns a pointer to the destination string. 1. Is it insider trading to purchase shares in a competitor? So it will copy the terminator before realizing it did, and stopping. acknowledge that you have read and understood our, Data Structure & Algorithm Classes (Live), Full Stack Development with React & Node JS (Live), Fundamentals of Java Collection Framework, Full Stack Development with React & Node JS(Live), GATE CS Original Papers and Official Keys, ISRO CS Original Papers and Official Keys, ISRO CS Syllabus for Scientist/Engineer Exam, A shorthand array notation in C for repeated values. How to pass a 2D array as a parameter in C? Although truncation to fit the destination buffer is a security risk and therefore a runtime constraints violation for strncpy_s, it is possible to get the truncating behavior by specifying count equal to the size of the destination array minus one: it will copy the first count bytes and append the null terminator as always: strncpy_s(dst, sizeof dst, src, (sizeof dst)-1); // writes five characters 'h', 'i', '\0', '\0', '\0' to dest, "strncpy(dest, src, 5) to a 6-byte dest gives: ", // truncation: writes two characters 'h', 'i', to dest2, https://en.cppreference.com/mwiki/index.php?title=c/string/byte/strncpy&oldid=140653, pointer to the character array to copy to, pointer to the character array to copy from, allocate a copy of a string up to specified size, overlap would occur between the source and the destination strings, K.3.7.1.4 The strncpy_s function (p: 447-448), 7.24.2.4 The strncpy function (p: 363-364), K.3.7.1.4 The strncpy_s function (p: 616-617), 7.21.2.4 The strncpy function (p: 326-327). I am trying to implement strcmp and strcpy to re-arrange names in alphabetical order and there is an issue with my name array initialization. 8. If the destination string is not large enough to store the . You can NOT delete the second line char *temp = strDest; and directly return strDest. cc by-sa 2.5, cc by-sa 3.0 cc by-sa 4.0 . I thought that assignments returned always "1" or true, if they were correct assigned. You do not have to consider the \0 at the end in the first string, it will be copied automatically from the second string as per logic Why strcpy and strncpy are not safe to use? Ifsrc1 src2 return -1. ins.style.display = 'block'; Steps: Create a function strtok () which accepts string and delimiter as an argument and return char pointer. The source string remains same after copying. , , , . This function only works with C style strings and not C++ style strings i.e. Affordable solution to train a team and make them project ready. c. source. How can I fix chips out of painted fiberboard crown moulding and baseboards? strcmp and strncmp implementation in glibc tagged C, glibc, GNU, Library, Programming, Software, www. Altering 60 amp dedicated circuit in the Garage. An array of characters is called a string. For example, the first call to strncpy_s () on line 5 of the sample program shown in Figure 1 assigns the value zero to r1 and the sequence hello\0 to dst1. Required fields are marked *. Let's rewrite our previous program, incorporating the definition of my_strcpy() function. Explanation:Hello is greater than Aticleworld because the first non-matching character in both words is H and A respectively, and H (72) evaluates as greater than A (65). strcpy implementation in c while ((*destination++ = *source++) != '\0'); Similar pages Similar pages with examples. Q3) Is strncpy leading to a segmentation fault. Create Your Own strcpy() String Copy Function | C Programming Example, C String Library and String Copy Function - strcpy(), C Programming Example: Implementing strcpy function, strcpy function from string.h implementation in C, Own implementation of strcpy() string function in C Programming, strcpy() and strncpy() functions | C Programming Tutorial. Generated on 2022-Aug-17 from project glibc revision glibc-2.35-168-g37fd2ac665 Powered by Code Browser 2.1 Generator usage only permitted with license. Line number 4 and 5 handle the scenario that source and destination memory must not be NULL. 7. version 2.1 of the License, or (at your option) any later version. Following is the declaration for strncpy() function. Also, some times require to create own strncpy function. What happens after crashing in a commercial flight simulator? The strcpy() function copies the string pointed to by src, including the terminating null byte ('\0'), to the buffer pointed to by dest.The strings may not overlap, and the destination string dest must be large enough . By using our site, you char* strcpy (char* dest, const char* src); Parameters: This method accepts the following parameters: dest: Pointer to the destination array where the content is to be copied. source and destination. Lets create a small application to test our own strncpy() function. var pid = 'ca-pub-1332705620278168'; What happens after crashing in a commercial flight simulator? By Nathan Beier at Jan 20 2021. How to do safe copy? Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The C programming language offers a library function called strcpy, defined in the string.h header file, that allows null-terminated memory blocks to be copied from one location to another.Since strings in C are not first-class data types and are implemented instead as contiguous blocks of bytes in memory, strcpy will effectively copy strings given two pointers to blocks of allocated memory. Agree Installing GoAccess (A Real-time web log analyzer). 2.) So lets create our own strncpy function that copies n characters from source to the destination buffer. The strncmp function compares not more than n characters (characters that follow a null character are not compared) from the array pointed to by s1 to the array pointed to by s2. Overlapping scrollable content. Return Value: After copying the source string to the destination string, the strcpy () function returns a pointer to the destination string. 4. Strcpy implementation in C; Strcpy implementation in C. 45,644 Solution 1. /* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. An array of characters is called a string. Hommer Smith Asks: Strcpy implementation in C So, I have seen this strcpy implementation in C: void strcpy1(char dest[], const char source[]) { int. Not the answer you're looking for? #include <stdio.h> #include <string.h> int main() { char str1[20] = "C programming"; char str2[20]; // copying str1 to str2 strcpy(str2, str1); puts(str2); // C . How to do safe copy? I needed this for a quick and dirty parser I was using and so hacked the sscanf implementation out of the friendliest library I . Appends the first num characters of source to destination, plus a terminating null-character. Estimating period of low frequency oscillations: autocorrelation vs. Oops, You will need to install Grepper and log-in to perform this action. You can use this code, the simpler the better ! What is the correct way to instantiate ImageShader? var container = document.getElementById(slotId); 3.) why we use strcpy in c. why we use strcpy in c for structure. Both copy the '\0'. ins.dataset.fullWidthResponsive = 'true'; It only takes a minute to sign up. If copying takes place between objects that overlap, the behavior is undefined. This function returns the pointer to the copied string. So the last assignment of (dest[i] = source[i]) returns '\0'? toggle sidebar. We make use of First and third party cookies to improve our user experience. By using this website, you agree with our Cookies Policy. lo.observe(document.getElementById(slotId + '-asloaded'), { attributes: true }); The strcpy() function is used to copy strings. I have working experience of different microcontrollers (stm32, LPC, PIC AVR and 8051), drivers (USB and virtual com-port), POS device (VeriFone) and payment gateway (global and first data). What is strtok_r() function in C language. The following program demonstrates the strcpy() function in action. if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'overiq_com-medrectangle-4','ezslot_4',136,'0','0'])};__ez_fad_position('div-gpt-ad-overiq_com-medrectangle-4-0'); In line 20, we have while loop, the while loops copies character from source to destination one by one. Unlike strncpy, strncpy_s does not pad the destination array with zeroes, This is a common source of errors when converting existing code to the bounds-checked version. The memory allocated to a destination should be large enough to copy the source string (including the terminating null character). Learn more, C in Depth: The Complete C Programming Guide for Beginners, Practical C++: Learn C++ Basics Step by Step, Master C and Embedded C Programming- Learn as you go. The strncat_s () function also ensures null termination of the destination string. For example, strncpy(s, t, n) copies at most n characters of t to s. Full Description in Appendix B. Connect and share knowledge within a single location that is structured and easy to search. } Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. The following example shows the usage of strncpy() function. The C library function char *strncpy (char *dest, const char *src, size_t n) copies up to n characters from the string pointed to, by src to dest. * string. In your custom_strncmp method, I'm not sure what correct behaviour should be if you call. Implement strncpy () function in C. Write an efficient function to implement strncpy () like function in C, which copies the given n characters from source C-string to another string. This website uses cookies. (adsbygoogle = window.adsbygoogle || []).push({}); Strncpy is not give the guaranty to append terminating null character in destination buffer. I don't think that concept exists, in C. While this code snippet may be the solution. Understanding volatile qualifier in C | Set 2 (Examples). It takes three arguments, its third argument (n) is the maximum number of characters to copy. . url url . How to use strxfrm function in C programming. disclaimer. The strcpy () Function in C. Syntax: char* strcpy (char* destination, const char* source); The strcpy () function is used to copy strings. How to Use strncpy() and implement own strncpy(). implement strcpy in c. strcpy function user made in c. use strcpy in c. c include for strcpy. You have to copy the NUL terminator character always or your string will be broken: you'll never know when/where it ends. Nice Article and thanks aticleworld. Your email address will not be published. At each iteration I check if the *s and *t are equal; if they are, I increment s and t. If they are not equal, I return their difference. What is if __name__ == '__main__' in Python ? Why would a loan company deposit a small amount into my account and require I send it back? What are the differences and similarities between records, coinductive records, and codatatypes? Warning: That file was not part of the compilation database. ================== Building calendar. it only works with strings of type. As corrected by the post-C11 DR 468, strncpy_s, unlike strcpy_s, is only allowed to clobber the remainder of the destination array if an error occurs. This version of strncat is a secure one. Are there examples of grassroots-level corruption in the history of socialism/communism? What is meant by zero point spin fluctuations? Thanks for contributing an answer to Stack Overflow! Q1) Why should you use strncpy instead of strcpy? In this situation, you should use memmove. container.style.width = '100%'; In a case where, the length of src is less than that of n, the remainder of dest will be padded with null bytes. * The function operates on null-ended strings. Also, note that functions whose names start with str are reserved, so neither of these are actually valid as "user-level" code. Code Browser 2.1 Generator usage only permitted with license. The strncpy function prevents buffer overflow because you put the length of bytes which you want to copy, but the condition is that the destination buffer should have sufficient space to copy the n bytes. Why was the size of the 1989 Intel i860 (aka 80680) memory bus 64bit? You do not have to consider the \0 at the end in the first string, it will be copied automatically from the second string as per logic. Some times people ask the questions to write a program to copy characters source to destination. If the input is NULL and all the tokens are extracted then return NULL. Note: If copying takes place between objects that overlap, the behavior is undefined. Here we have used function memset() to clear the memory location. Asking for help, clarification, or responding to other answers. Both strcpy1() and strcpy2() does the same. strcpy2() does the copying first, then the compares. The my_strcpy() function accepts two arguments of type pointer to char or (char*) and returns a pointer to the first string. Use MathJax to format equations. Let's see an example to understand the concept. Transposing columns into rows in QGIS Attribute table. The best answers are voted up and rise to the top, Not the answer you're looking for? printf or print function in C takes a formatting string and couple of optional variables as input and outputs strings to console while converting input variables to strings. affiliate-disclosure In line 12 to 17, we have a while loop, the while loops copy character from source to destination one by one and incrementing the source and destination pointer by 1. The return value is to. sp_executesql Not Working with Parameters, How to get standards errors of the parameters of a non-linear model (R and Excel). Q4) Describe the scenario when the behavior of strncpy becomes undefined. Thats all about strncpy() implementation in C. No votes so far! You can check the below video to understand the working of strncpy in C programming with example code. Why were nomadic tribes (like the Mongols) from the Eurasian steppes a much reduced threat from the 15th century onwards? I have working experience of different microcontrollers (stm32, LPC, PIC AVR and 8051), drivers (USB and virtual com-port), POS device (VeriFone) and payment gateway (global and first data). 1) Copies at most count characters of the character array pointed to by src (including the terminating null character, but not any of the characters that follow the null character) to character array pointed to by dest. Blog Posts Interview Questions On bitwise Operators C, Interview Questions On Memory Allocation C, Machine Learning, Data Science and Deep Learning, Statistics for Data Science, Data and Business Analysis. We provide programming data of 20 most popular languages, hope to help you! All alphabetic characters in the two arguments. strncmp function compares the two strings lexicographically. You can NOT delete the second line char *temp = strDest; and directly return strDest. What was the purpose of the overlay number field in the MZ executable format? It is the responsibility of the program to make sure that the destination array has enough space to accommodate all the characters of the source string. Notice that source is preceded by the const modifier because strcpy() function is not allowed to change the source string. * s1 and s2 are converted to lowercase before the comparision. articles full forms errors & fixes Parameter names are important (even more important than good names for local variables) because they may be the only documentation about how the function should be called. To learn more, see our tips on writing great answers. Include int main printf nnttStudytonight - Best place to learnnnn. Printing the Adderss of an Object of Class in C++. A standalone sscanf implementation (for the esp8266) January 7, 2015, 2:05 am. Both copy the \0 (NUL terminator) character. 1.) I've mentioned alternate methodical syntax, where in case someone might wonder the code output. I'm not at all sure what you mean by "correct assigned". Here is full implementation. 4.) Learn more, C in Depth: The Complete C Programming Guide for Beginners, Practical C++: Learn C++ Basics Step by Step, Master C and Embedded C Programming- Learn as you go. So, I have seen this strcpy implementation in C: Which to me, it even copies the \0 from source to destination. Making statements based on opinion; back them up with references or personal experience. tutorials technology. var ffid = 1; Many compilers will insert unneeded jmp or other branch instructions when you insert unnecessary "else" statements. I am an embedded c software engineer and a corporate trainer, currently, I am working as senior software engineer in a largest Software consulting company . How to implementation of strcpy() string function in C Programming.What is strcpy function?strcpy function takes two strings as parameter and copy second st. * function are expected to contain a null character (\0) at the end of the. Mathematica not able to output simple expressions for numerical sums. Set the image for switch button in flutter, Firebase Google users not showing in Firebase Console Authentication. (adsbygoogle = window.adsbygoogle || []).push({}); Frequency approaches. Contribute to gcc-mirror/gcc development by creating an account on GitHub. Given below is a C program to copy n number of characters from source string to destination string using strncpy library function , Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. It compares the two strings character by character starting from the first character until the characters in both strings are equal or a null character is encountered. What would an example of an "incorrect assignment" be? Accessing There is a control string "%s" used for accessing the string till it encounters \0. You have to copy the NUL terminator character always or your string will be broken: you'll never know when/where it ends. [1] This means a string cannot contain the zero code unit, as the first one seen marks the end of the string. The following example shows the usage of strncpy() function. You can see below C program for better understanding, Your email address will not be published. How to change behavior of underscore following a predefined command? explain strcpy function in c. ins.className = 'adsbygoogle ezasloaded'; Need to change the copy constructor by the following: Test (const Test &t) { cout << "Copy Constructor Called\n"; } The fun () function returns a value. Expandable way to tell apart a character token and an equivalent control sequence. Another important point to note about strcpy() is that you should never pass string literals as a first argument. In line 14, the return statement returns the character pointer to the calling function. This page has been accessed 353,429 times. After the loop stops, is returned a pointer to the result. This is padding null character \0, but not 0 Both versions do that. Strncat instead of strncat); or, the Microsoft versions of the 'safe' functions have _l as a suffix. Be the first to rate this post. This function copies the entire string to the destination string. C strcpy() function with programming examples for beginners and professionals covering concepts, control statements, c array, c pointers, c structures, c union, c strings and more. This will cause error for the returned content. The GNU C Library is free software; you can redistribute it and/or. Inside while() we copy char by char and moving pointer to the next. It takes three parameters and you must include string.h header file in your C program. Find the data you need here. - AticleWorld, How to use and implement memchr in C - AticleWorld, strchr function in C/CPP with its applications - AticleWorld, Use of strrchr function in C/C++ - AticleWorld, How to use and Implement own strcat in C - AticleWorld, strtok() function in C with example code - AticleWorld, How to use and implement strspn in C - AticleWorld, abs labs llabs functions in C/C++ - AticleWorld, div, ldiv, lldiv, functions in C - AticleWorld, atexit function in C/C++, you should know - AticleWorld, Use of exit function in C/C++ with Examples - AticleWorld, strlen function in C/C++ with usage - AticleWorld. In line 18, we have assigned the base address of the destination to start, this is necessary otherwise we will lose track of the address of the beginning of the string. What are the default values of static variables in C? Your email address will not be published. ins.style.height = container.attributes.ezah.value + 'px'; Both versions do that. ASCII value of the null character (\0) is 0. What is strncat() Function in C language? The statement in line 13, appends a null character ('\0') to the string. The C library function char *strncpy(char *dest, const char *src, size_t n) copies up to n characters from the string pointed to, by src to dest. So it will copy the terminator before realizing it did, and stopping. So to resolve this issue we must use add a trailing null character explicitly in the last of the destination buffer. Asking for help, clarification, or responding to other answers. Note: C standard only explains that the return value ofstrncmp function returns an integer greater than, equal to, or less than zero, accordingly, as the possibly null-terminated array, pointed to by s1 is greater than, equal to, or less than the possibly null-terminated array pointed to by s2. both the strings and then it will return the compared result in the form of int value which in turn has its own significance. This will compare both the arguments i.e. Here is full implementation. *. affiliate-disclosure Train Ticket Booking System Project In C With Source Code. The strncpy function copies no more than n characters (characters that follow a null character are not copied) from the array pointed to by src to the array pointed to by dest. After the loop stops, the '\0' is copied in *saver and a pointer to the result is returned. When the first not matching character in left-string (s1) has a greater ASCII value than the corresponding character in right-string(s2), then it returns a value greater than zero. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); About A return ends the function right there. Parameters: This method accepts the following parameters: Return Value: After copying the source string to the destination string, the strcpy() function returns a pointer to the destination string. var slotId = 'div-gpt-ad-overiq_com-medrectangle-3-0'; How to dynamically allocate a 2D array in C? I think you've misinterpreted the definition of strncat, which says,. Note that strcpy2() does the assignment (the copying) first, then the comparison. strncmp function does not compare more than n characters of given strings s1 and s2. Doesn't guarantee nul termination; it's just that you won't overflow your input buffer. Does guarantee that every byte of the destination str will be written either with data preceding srcs nul termination, or nul characters. The state array cannot be printed out on the console as To learn more, see our tips on writing great answers. You can handle the scenario as your requirement and if possible then use the library function. Dive Into Python has already been fully or partially translated into several languages. strcmp implementation in C !!! Enter your email address to subscribe to new posts. What was the purpose of the overlay number field in the MZ executable format? In line number 8, I am holding the starting address of the destination buffer and I will use it to return because in later line I am incrementing the destination pointer. Lets see an example code to understand the functionality of the strncpy function. Your function might return 0 or non-zero, or crash, depending on what's after the end of the string. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); About See the below table for better understanding. 3. If the strncpy function encounters a null character in s2, the function will add null characters to s1 until n characters have been written. License as published by the Free Software Foundation; either. It takes three arguments, its third argument (n) is the maximum number of characters to copy. strcpy implementation in c. Copy. For example, it will not return correct value (should be 22) will checking the length of returned char *. How it works: Basically strcmp works in such a way that, it . Positive value <= The first character that does not match has a greater value in s1 than in s2. Using strcpy () function to copy a large character array into a smaller one is dangerous, but if the string will fit, then it will not be worth the risk. When the first not matching character in left-string (s1) has a lesser ASCII value than the corresponding character in right-string(s2), then it returns a value lesser than zero. Note that strcpy does not perform bounds checking, and thus risks overrunning from or to. As a result, the compiler generates a temporary entity, which is then copied to t2 using the original program's copy function Object () { [native code] } (The temporary object is passed as an . I am an embedded c software engineer and a corporate trainer, currently, I am working as senior software engineer in a largest Software consulting company . Check if extracting the tokens for the first time then initialize the input with it. // without the check on line 4, the new string overwrites the old including the null deliminator, causing the copy unable to stop. 7. s1 This is the first string to be compared. 5 ways to check if two integers have opposite signs. char *strncpy (char *destination, char *source, size_t n); Or we can simply write the arguments as (str1, str2, size); source: A valid string. ins.dataset.adClient = pid; The following code will copy the first num characters of the source to the array pointed by destination, including the terminating null character. 2. Both copy the \0 (NUL terminator) character. What is the R squared of a regression where none of the variables are collinear? If count is reached before the entire array src was copied, the resulting character array is not null . ins.style.minWidth = container.attributes.ezaw.value + 'px'; It may have many parsing errors. The length of the destination string is greater than or equal to the source string. The functions whose names start with str are reserved, so use any other variables or naming types. It's good of you to write a custom version with an extra parameter to make it safe, but that's not what the question asked for. Online since 1996, die.net hosts the collective 'net projects of a few dozen friends in the U.S. 2017 May 20 Added a CDN to improve page load time 2014 Oct 12 Switched to responsive CSS to improve mobile experience Apr 13 Dictionary.die.net shut down 2013 Nov 18 Removed gadgets for now-defunct iGoogle 2011 Mar 05 Added Home Price Graph, a tool for checking housing price changes in your area rev2022.12.2.43073. The text file I have has a unique ID's in one coloumn. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. It is recommended not to advance the input pointers to the source and destination memory spaces, since the pointers will be used in main right away. We provide programming data of 20 most popular languages, hope to help you! Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. While this code snippet may be the solution, Continuous delivery, meet continuous security, Help us identify new roles for community members, Help needed: a call for volunteer reviewers for the Staging Ground beta test, 2022 Community Moderator Election Results, Function to copy char pointer content crashes when printing second index of copy, Passing member function using boost::bind, Copying a string to an array implementation C, Copying characters from a source string to a buffer - C. String vs String Literal: Direct assignment or strcpy/strncpy? The C library function char *strncpy(char *dest, const char *src, size_t n) copies up to n characters from the string pointed to, by src to dest. It copies string pointed to by source into the destination. For example, it will not return correct value (should be 22) will checking the length of returned char *. Making statements based on opinion; back them up with references or personal experience. What is strcoll() Function in C language? sp_executesql Not Working with Parameters, PSE Advent Calendar 2022 (Day 1): A festive Sudoku. window.ezoSTPixelAdd(slotId, 'stat_source_id', 44); Code Review Stack Exchange is a question and answer site for peer programmer code reviews. How to deallocate memory without using free() in C? Write an efficient function to implement strncpy() like function in C, which copies the given n characters from source C-string to another string. But if my_strcpy(tmp + 1, tmp) is the case, the program will crash, because the last terminator'\0' of tmp will be erased because they share memory, and then dst is relatively behind tmp. Guest Article Thus it will copy the terminator and stops. char *mstrtok(const char *str,const char *del) {static char *sp = NULL ; static int pos = 0; //this is the first time the function is getting called Definitions [ edit] A string is defined as a contiguous sequence of code units terminated by the first zero code unit (often called the NUL code unit). Thus it will copy the terminator and stops. The strcpy is a library function available in string library in C, and is used to copy the content of one string to another. After the loop stops, the value 0 is returned. Agree By using this website, you agree with our Cookies Policy. The output of strcpy() and my_strcpy() is same that means our program is working as expected.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'overiq_com-box-4','ezslot_9',137,'0','0'])};__ez_fad_position('div-gpt-ad-overiq_com-box-4-0'); // copy the contents of ch_arr1 to ch_arr2, // signal to operating system program ran fine, Operator Precedence and Associativity in C, Conditional Operator, Comma operator and sizeof() operator in C, Returning more than one value from function in C, Character Array and Character Pointer in C, Machine Learning Experts You Should Be Following Online, 4 Ways to Prepare for the AP Computer Science A Exam, Finance Assignment Online Help for the Busy and Tired Students: Get Help from Experts, Top 9 Machine Learning Algorithms for Data Scientists, Data Science Learning Path or Steps to become a data scientist Final, Enable Edit Button in Shutter In Linux Mint 19 and Ubuntu 18.04, Installing MySQL (Windows, Linux and Mac). In a case where the length of src is less than that of n, the remainder of dest will be padded with null bytes. It is important to note that strcpy() function do not check whether the destination has enough size to store all the characters present in the source. It is the reason it is unsafe to use. The while loop will run until n reaches the value 0, at each iteration the current character that ct points to is copied in *saver. Examples from various sources (github,stackoverflow, and others). In this C code, I am copying the string from an array src to the array dest. if(ffid == 2){ A-143, 9th Floor, Sovereign Corporate Tower, We use cookies to ensure you have the best browsing experience on our website. Open strcmp implementation in c using pointers. Save my name, email, and website in this browser for the next time I comment. What is strncmp() Function in C language? Name. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I'm not sure that returning null and doing no copy is the standard way to avoid buffer overflow. ~ c++ . Why does Tom Riddle ask Slughorn about Horcruxes, at all? Thanks for contributing an answer to Code Review Stack Exchange! However there doesn't seem to be a corresponding sscanf. The second call on line 6 assigns a non-zero value to r2 and the sequence \0 to dst2. CGAC2022 Day 1: Let's build a chocolate pyramid! I think you've misinterpreted the definition of strncat, which says. strcpy, strncpy - copy a string Synopsis #include <string.h> char *strcpy(char *dest, const char *src); char *strncpy(char *dest, const char *src, size_t n); Description. What does it mean that "training a Caucasian Shepard dog can be difficult"? Read our, // Function to implement `strncpy()` function, // return if no memory is allocated to the destination, // take a pointer pointing to the beginning of the destination string, // copy first `num` characters of C-string pointed by source, // the destination is returned by standard `strncpy()`, // Copies the first `num` characters of the source to destination. Copying the null terminator is correct. So, I have seen this strcpy implementation in C: Which to me, it even copies the \0 from source to destination. When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com. Copying stops when source points to the address of the null character (\0) or n become 0. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The syntax of the strncpy is. Code examples and tutorials for Strcpy C Implementation. Create a static variable input to maintain the state of the string. 13 Years Ago mvmalderen 0 3K Views. Affordable solution to train a team and make them project ready. C Language: strncpy function (Bounded String Copy) In the C Programming Language, the strncpy function copies the first n characters of the array pointed to by s2 into the array pointed to by s1.It returns a pointer to the destination. When the migration is complete, you will access your Teams at stackoverflowteams.com, and they will no longer appear in the left sidebar on stackoverflow.com. How to use and Implement own strcmp in C - AticleWorld, How to use and implement memchr in C - AticleWorld, strchr function in C/CPP with its applications - AticleWorld, Use of strrchr function in C/C++ - AticleWorld. How to Declare and Initialize an Array of Pointers to a Structure in C? C strcpy() In this tutorial, you will learn to use the strcpy() function in C programming to copy strings (with the help of an example). var cid = '9225403502'; strcpy2() does the copying first, then the compares. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. The esp8266 standard SDK include a sprintf like function called os_sprintf. Code examples and tutorials for Strcpy Implementation In C. Find the data you need here. 6. )The behavior is undefined when access occurs past the end of either array s1 or s2. Since several people have asked: strncpy: 1. var lo = new MutationObserver(window.ezaslEvent); If characters of both string s1 and s2 are identical till n characters, then strncmp() function return 0. Copying stops when source points to the address of the null character ('\0'). This will cause error for the returned content. Problem with strcpy (): The strcpy () function does not specify the size of the destination array, so buffer overrun is often a risk. This function accepts two arguments of type pointer to char or array of characters and returns a pointer to the first string i.e destination. What type of verb is EAT:FEED, KNOW:INFORM. rev2022.12.2.43073. Vector of Vectors in C++ STL with Examples. Printf working principle. The time complexity of the above solution is O(num). In a case where, the length of src is less than that of n, the remainder of dest will be padded with null bytes. Let's create our own version of strcpy() function. You're wrong. What's the retcon for what Leia says in her R2-message, given the events of Kenobi? Write versions of the library functions strncpy, strncat and strncmp, which operate on the most n characters of their argument strings. It doesnt append the source string to the destination string. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Should I apply to an academic tenure-track job even if I am not a 100% fit? disclaimer. Appends the first num characters of source to destination, plus a terminating null-character. The strncpy function is a safer version of strcpy to copy a string from a source to a destination buffer. LKML Archive on lore.kernel.org help / color / mirror / Atom feed * [PATCH net 0/4] net: dsa: Use strncpy() for ethtool::get_strings @ 2018-03-02 0:25 Florian Fainelli 2018-03-02 0:25 ` [PATCH net 1/4] net: dsa: b53:" Florian Fainelli ` (4 more replies) 0 siblings, 5 replies; 10+ messages in thread From: Florian Fainelli @ 2018-03-02 0:25 UTC (permalink / raw) To: netdev Cc: Florian Fainelli . The functions whose names start with str are reserved, so use any other variables or naming types. If the source buffer is longer than the number of bytes that you want to copy, then no null character is implicitly appended at the end of the destination buffer. Required fields are marked *. This page was last modified on 27 June 2022, at 13:17. 3.) What if the size of dest is unknown in the function strcpy? ins.id = slotId + '-asloaded'; Do NOT follow this link or you will be banned from the site. 6.) This function accepts two arguments of type pointer to char or array of characters and returns a pointer to the first string i.e destination. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. var alS = 1021 % 1000; So you must avoid the use of strncpy when the memory of source and destination is overlapped. n The maximum number of characters to be compared. Which to me, it will break when trying to assign \0 from source to dest. The exercise can be found at page 121 in K&R second edition. , Then he will go to the last digit first, but src has not yet reached the last digit, indicating that it is still a normal character, then the terminator'\0' existing in the original memory will be erased . So here in the below section, I shall describe the way to create the strncmp() function or you can say that we will see the implementation of strncmp in C. Lets see an example code to understand the functionality of the strncmp in C. In this C code, we will compare two given string. 4.) C program to Copy string without using strcmp function by creating our own function which uses pointers. *. From: Kees Cook <keescook@chromium.org> To: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: "Tobin C. Harding" <me@tobin.cc>, Jann Horn <jannh@google.com>, "Tobin C. Harding" <tobin@kernel.org>, Shuah Khan <shuah@kernel.org>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Kernel . Your email address will not be published. var ins = document.createElement('ins'); * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined . What I want to do is index data based on ID using Btrees.The following is my code: #include <iostream> #include <cstdlib> #include <fstream> #include <string.h> #include <sstream> #include <stdio.h> #include <cctype> using namespace std; const int MaxKeys = 11; // max number of keys in a node const int MaxKeysPlusOne = MaxKeys + 1 . n is the maximum number of characters in source you you want to copy, and bfsize doesn't exist in the standard version of strncat. Blog Posts We are sorry that this post was not useful for you! should i use strcpy in c strcpy use in c strcpy c library strcpy in c in funciont implement strcpy in c strcpy function user made in c strcpy() c use strcpy in c c include for strcpy strcpy syntax in c what does strcpy return in c strcpy what is it in c strcpy in c meaning strcpy in c why we use strcpy in c why we use strcpy in c for structure . char* strncpy(char* destination, const char* source, size_t num); The C99 standard adds the restrict qualifiers to the prototype: char* strncpy(char* restrict destination, const char* restrict source, size_t num); The strncpy() function copies num characters from the null-terminated string pointed to by source to the memory pointed to by destination and finally returns the pointer destination. Sometimes peoples require to create their own strncmp function for their project. In a case where the length of src is less than that of n, the remainder of dest will be padded with null bytes. dest This is the pointer to the destination array where the content is to be copied. Note: Below function only to understand the working of strncpy. MathJax reference. Save my name, email, and website in this browser for the next time I comment. The while loop will run until n reaches the value 0, or until the characters that s and t point to are not equal. The prototype of the strncpy () is: char* strncpy (char* destination, const char* source, size_t num); The C99 standard adds the restrict qualifiers to the prototype: If the source string is shorter than n characters (number of characters want to copy), then the destination array is padded with zeros until a total of n characters have been written to it. We can replace the above lines of code with a single line of code. C Programming: C String Library and strcpy() Function in C Programming.Topics discussed:1 . - AticleWorld, Implementation of memmove in c language - AticleWorld, How to use and Implement own strcmp in C - AticleWorld, How to use strxfrm function in C programming. Both copy the terminator, thus both are correct. Difference Between malloc() and calloc() with Examples, Dynamic Memory Allocation in C using malloc(), calloc(), free() and realloc(). Find centralized, trusted content and collaborate around the technologies you use most. Generated on 2017-Dec-13 from project libiberty revision 255606 Powered by Code Browser 2.1 Generator usage only permitted with license. 7 C++14 std:unique\u ptr std:make\u unique RAII [1] At each iteration the value that t points to is copied in to *s. Syntax. You're wrong. Favourite Share. Following is a syntax: int strcmp (const char * str1, const char * str2); This syntax represents that str 1 and str 2 are the two strings as parameters inside the function. How to sustain and realize a collaboration? Digital logic design tutorial (DLD Tutorial):https://www.youtube.com/watch?v=baF-cxSl8TA&list=PL4hV_Krcqz_J4K8dEFsq. dest: Pointer to the destination array where the content is to be copied. )The behavior is undefined when either s1 or s2 is the null pointer. Since modifying a string literal causes undefined behaviour, calling strcpy() in this way may cause the program to crash. Both copy the terminator, thus both are correct. What would be the correct option, copying \0 or not? Note: C11 introduce safer version strncpy is strncpy_s. strcpy() is a standard library function in C/C++ and is used to copy one string to another. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I'm not at all sure what you mean by "correct assigned". This is a toupper and tolower implementation for whole c-strings, without making use of the existing toupper and tolower functions for characters :) example: char s[]="Hello, beautiful world!"; stoupper(s); // s now contains: `HELLO, BEAUTIFUL WORLD! stolower(s); // s now contains: `hello, beautiful world . By using this site, you agree to the use of cookies, our policies, copyright terms and other conditions. The strncpy function is a safer version of strcpy to copy a string from a source to a destination buffer. You can see the highlighted portion of the code. Syntax: char* strcpy (char* destination, const char* source); Compile errors for iOS app from Flutter/IntelliJ editor? Both copy the terminator, thus both are correct. Are you looking for a code example or an answer to a question use of strcpy in c? Which episode of "Space: Above and Beyond" has the famous regulators quote? Both copy the NUL character to the end of the destination array. Also, note that functions whose names start with str are reserved, so neither of these are actually valid as "user-level" code. So it will copy the terminator before realizing it did, and stopping. Related code examples. Complete Interview Preparation- Self Paced Course, Data Structures & Algorithms- Self Paced Course, C program to copy string without using strcpy() function. In C it is present in string.h header file and in C++ it is present in cstring header file. What would be a recommended interest rate for an unsecured loan to individuals with mediocre credit rating and income close to expenses? The strncpy function prevents buffer overflow because you put the length of bytes which you want to copy, but the condition is that the destination buffer should have sufficient space to copy the . What would an example of an "incorrect assignment" be? I thought that assignments returned always "1" or true, if they were correct assigned. Does Weapon Focus feat chain really suck? At this point string pointed to by start contains all characters of the source except null character ('\0'). How do astronomers measure the parallax angle? How to remove trailing newline character from fgets input? strncmp function does not compare more than n characters of given strings s1 and s2. It copies string pointed to by source into the destination. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, implementations of strncmp, strncat, strncpy, Continuous delivery, meet continuous security, Help us identify new roles for community members, strend, function that checks the occurence of a pattern at the end of a string, Functional-style linked list written in C, Alternative to using strncpy() as 'safe' version of strcpy(), Hash table implemented in C with open addressing, Replacing 1960s Motor Capacitor - Vintage Sewing Machine, What is the term for this derivation: "Cheeseburger comes from Hamburger" but the word hamburger didn't refer to ham. container.appendChild(ins); The length of a string is the number of code units before the zero code unit. How to find the index of the item, the first time appears? 3. Let us compile and run the above program that will produce the following result , Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. The C library function char *strncpy (char *dest, const char *src, size_t n) copies up to n characters from the string pointed to, by src to dest. 5.) Just a few minor points, you don't need that "else" in there. There is a lot of scenarios that is not handled in this function. The string arguments to the. In other words, we can say that it replaces the content of destination string by the content of source string. If characters of both string s1 and s2 are identical till n characters, then strncmp() function return 0. Is there a rule for spending downtime to get info on a monster? , appends a null character ( \0 ) or n become 0 ( GitHub, stackoverflow and... Contributing an answer to a destination buffer this Post was not part of the functions. Because strcpy ( ) function scenario when the memory of source string ask the questions to write a program copy... Functions whose names start with str are reserved, so use any other variables or naming types the. Example char string [ 50 ] ; string of length 50 characters ; Compile errors iOS... Has been dynamically allocated to a segmentation fault returns a pointer to char or array of to! Commercial flight simulator standard library function and baseboards some times people ask the questions to write a program to.. Terminator, thus both are correct released under the GNU Lesser General Public answer to Review! Method, i have seen this strcpy implementation in glibc tagged C, glibc, GNU, library programming. Above program is executed, it even copies the \0 from source to a segmentation fault if! S in one coloumn & technologists share private knowledge with coworkers, developers... In this Browser for the first n character copied from src to the copied string that is null! ) in C it is the number of characters from one string to another string that has been dynamically?. Never pass string literals as a parameter in C it is a standard library function: article. 121 in K & R second edition Flutter/IntelliJ editor in action able to output simple expressions for sums! Highlighted portion of the null pointer should i apply to an academic tenure-track job even if i am to... If count is reached before the zero code unit agree to our terms service! Of socialism/communism you translate it into another language and would like to be.... Copied in * saver and a pointer to the string till it encounters \0 C, glibc,,! Can handle the scenario as your requirement and if possible then use library... We can say that it replaces the content is to be a corresponding sscanf have used function memset )... 1999 Apple Computer, Inc. all rights reserved ( num ) great answers its own significance your custom_strncmp method i! Example of an Object of Class in C++ for numerical sums in s2 with license copying the string till encounters. Flutter/Intellij editor create a small amount into my account and require i send it back strncat_s. What is strcoll ( ) function in C | Set 2 ( examples ) (! Agree to the result is returned transparent/wallpaper-showing Flutter app instead of strncat, which is used to copy without... * strcpy ( char * destination, plus a terminating null-character first string destination... A chocolate pyramid: let 's rewrite our previous program, incorporating definition! Can not install flutter_plugins_tools, dependency error, how to pass a 2D array as suffix! Source ) ; the length of returned char * source ) ; 3. tutorial ): a festive.. Design / logo 2022 Stack Exchange window.adsbygoogle || [ ] ).push ( { } ) Compile! Programming, Software, www a non-zero value to r2 and the sequence & # x27 s... Accessing the string till it encounters \0 container.attributes.ezah.value + 'px ' ; this function is string... Asking for help, clarification, or responding to other answers t to... On 27 June 2022, at 13:17 following is the maximum number characters. Not match has a lower value in s1 than in s2 should ) be better named, e.g other! Which in turn has its own domain own significance '__main__ ' in Python downtime get! May be the solution implementation out of painted fiberboard crown moulding and baseboards program for better,! Copy n number of characters and returns a pointer to char or array of characters and a... C with source code regression where none of the destination buffer MZ executable format me know following is number. Example to understand the concept in case someone might wonder the code GoAccess ( Real-time! What 's after the end of the license, or responding to other answers strncpy... To another has the famous regulators quote tutorial ( DLD tutorial ) https! By-Sa 3.0 cc by-sa 3.0 cc by-sa 2.5, cc by-sa 4.0 is 0 strDest... Your function might return 0 uses Pointers Reference Pages - Strn ( 3 ) ( e.g require to create strncpy! Github, stackoverflow, strncpy implementation in c website in this function accepts two arguments of pointer! File was not part of the GNU C library is Free Software you! A non-zero value to r2 and the sequence & # x27 ; s in one coloumn Pointers... Or NUL characters non-zero value to r2 and the sequence & # x27 t. Syntax: char * temp = strDest ; and directly return strDest to a. Methodical syntax, where in case someone might wonder the code time appears with mediocre credit rating income... Const modifier because strcpy ( ) we copy char by char and moving to. To subscribe to new posts implement strcpy in c. what if the destination.... When either s1 or s2 function also ensures null termination of the compilation database slotId... Following program demonstrates the strcpy ( ) does the copying ) first, then the compares container.attributes.ezaw.value 'px! C include for strcpy implementation in c. C include for strcpy implementation in glibc tagged C glibc! ; Compile errors for iOS app from Flutter/IntelliJ editor ] ) returns '\0 ' ) to the result ; to. It is unsafe to use loop stops, the first time appears the const because... Array dest encounters \0 up with references or personal experience references or personal experience append the source (. This for a code example or an answer to a destination should large! Other words, we can replace the above solution is O ( num ) ; in there may the... Affiliate-Disclosure train Ticket Booking System project in C | Set 2 ( examples ) modified on 27 June 2022 at! And dirty parser i was using and so hacked the sscanf implementation ( for the next i. The time complexity of the GNU Free Documentation license your function might return 0 strncpy implementation in c comparision second call line! User experience argument ( n ) is the standard way to avoid buffer.... Review Stack Exchange functionality of the destination array where the content is to be copied and. Program, incorporating the definition of strncat, which is used for copying n characters of their argument strings any! Adsbygoogle = window.adsbygoogle || [ ] ).push ( { } ) ; s... First, then the comparison '\0 ' ) function for their project array can not null! Not the answer you 're looking for which uses Pointers the 15th century onwards % ' ; strcpy2 ( is. Are the differences and similarities between records, and website in this Browser for the esp8266 ) 7! Nul termination, or ( at your option ) any later version so you must include string.h header file in. Even if i am trying to assign \0 from source to destination and third party cookies to improve our experience... For Teams is moving to its own domain memory must not be published are converted to lowercase the. 80680 ) memory bus 64bit of length 50 characters be the correct option, copying \0 or not Excel! Difficult '' a monster of an `` incorrect assignment '' be pointed to source. Name array initialization alS = 1021 % 1000 ; so you must avoid the use of becomes... Rss feed, copy and paste this URL into your RSS reader Lesser! To understand the functionality of the parameters of a regression where none of the 1989 Intel i860 ( 80680. That you should never pass string literals as a first argument browse other questions tagged, developers! Compilation database copied string for better understanding, your email address to subscribe to this RSS,... To find the index of the null character ( '\0 ' ) source code function does not bounds. And baseboards program is executed, it even copies the \0 ( NUL terminator ) character code examples tutorials. The calling function in a commercial flight simulator, 2015, 2:05 am think you 've the... Item, the '\0 ' ) else & quot ; in there { } ;. Str are reserved, so use any other variables or naming types use strncpy instead of,. Make them project ready and cookie policy the strncpy function that copies n characters of source string Advent 2022... Use strcpy in C autocorrelation vs. Oops, you agree to our terms of service privacy... Include int main printf nnttStudytonight - best strncpy implementation in c to learnnnn 2017-Dec-13 from project libiberty revision 255606 Powered by Browser! Thus it will copy the \0 from source to destination, const char * destination, char. Previous program, incorporating the definition of my_strcpy ( ) in this way may the. And share knowledge within a single location that is not allowed to change behavior of underscore following a predefined?. Is structured and easy to search on opinion ; back them up with references or personal experience with.... Is reached before the comparision much reduced threat from the 15th century onwards and. They are released under the GNU Free Documentation license dest: pointer to copied... ) from the 15th century onwards index of the above lines of code with a single of... Nnttstudytonight - best place to learnnnn memory without using strcmp function by creating an account on GitHub modified on June. The strcpy ( ) function in C: which to me, it will when. Make use of strcpy to copy the terminator, thus both are correct ;!: ` strncpy implementation in c, beautiful world a pointer to char or array of characters to copy: above and ''!