In this post, you will learn a program to write a String copy function. C programming language has many built-in string functions including the strcpy() function. The strcpy() function copy text from one string to another. To understand the working of string copy function, we write a program that copies text from one string to another.

This program is written using Dev-C++ compiler installed on a Windows 7 64-bit machine and it is intended for beginners of C programming.

Problem Definition

The program reads a string and then copy that string to another string and display the results.

Each string is an array of characters with a null character at the end of the string. Make sure that the size of the string is same or greater than string 2 size, otherwise, there will be problem copying string 1 to string 2.

Start copying string character by character from string 1 to string 2, until we reach a null character.

Assign a null character to the string 2 when all characters of string 1 are copied successfully. This is because every string in C language must end with a ‘\0’.

For Example:-

Suppose the program reads “hello” to string 1, and then the starts copying string 1 to string 2 one character at a time until a null is encountered. See figure below.

Flowchart – Program to Write a String Copy Function

Program Code

/* C Program to Write Strcopy () Function */

#include 
#include 
int main ()
{


char s1 [10];
char s2 [10];
int i;
void strcopy (char s2 [10], char s1 [10]);

/* Read the String 1 */

printf ("Enter String 1 :");
gets (s1);

/* Copy the String 1 to String 2 */

strcopy (s2, s1);

/* Print both the functions */

for (i=0; i

Output