C program to copy string without using strcpy() function

Last Updated : 15 Dec, 2024
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In C, the strcpy() function is commonly used for copying strings, but in this article, we will learn how to copy strings without using strcpy() function.

The simplest method to copy string without using strcpy() function is by using a loop. Let’s take a look at an example:

C 
#include <stdio.h>

void copy(char *src, char *dst) {
    int i = 0;

    // Copy each character from source to destination
    while (src[i] != '\0') {
        dst[i] = src[i];  
        i++;
    }

    // Null terminate destination string
    dst[i] = '\0';
}

int main() {
    char src[] = "Hello, Geeks!";
    char dst[50];

    // Copy the string src to dest
    copy(src, dst);  
    printf("%s", dst);
    return 0;
}

Output
Hello, Geeks!

Explanation: The most straightforward approach is to copy each character from the src string to the dest string using a loop. We continue copying characters until we encounter the null terminator ('\0'), which indicates the end of the string.

There are also a few other methods in C to copy string without using strcpy() function. Some of them are as follows:

Using Pointers

Instead of using array indexing, we can use pointers to traverse the source and destination strings. We simply move the pointer in the source string and assign its value to the destination string.

C 
#include <stdio.h>

void copy(char *src, char *dest) {
  
    // Copy each character from source to
  	// destination using pointers
    while (*dest++= *src++ );
}

int main() {
    char src[] = "Hello, Geeks!";
    char dest[50];

  	// Copy src to dest
    copy(src, dest);
  
    printf("%s", dest);
    return 0;
}

Output
Hello, Geeks!

Using memcpy()

The memcpy() function is part of the C standard library and can be used to copy a specified number of bytes from one memory location to another. This is useful for copying strings when you know their length in advance.

C 
#include <stdio.h>
#include <string.h>

void copy(char *src, char *dest) {
  
    // Copy the string using memcpy
    memcpy(dest, src, strlen(src) + 1);
}

int main() {
    char src[] = "Hello, Geeks!";
    char dest[50];
 
    // Copy the string src to dest
    copy(src, dest);
  
    printf("%s", dest);
    return 0;
}

Output
Hello, Geeks!

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C program to copy string without using strcpy() function

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Pushpanjali chauhan
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