C Programming: Copy one string into another string

Last update on October 24 2025 12:11:25 (UTC/GMT +8 hours)

8. Copy String

Write a program in C to copy one string to another string.

Sample Solution:

C Code:

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

int main() {
    char str1[100], str2[100]; // Declare two character arrays to store strings
    int i; // Declare a variable for iteration

    printf("\n\nCopy one string into another string :\n"); // Display information about the task
    printf("-----------------------------------------\n");
    printf("Input the string : ");
    fgets(str1, sizeof str1, stdin); // Read a string from the standard input (keyboard)

    /* Copies string1 to string2 character by character */
    i = 0; // Initialize the iteration variable
    while (str1[i] != '\0') { // Loop until the end of the first string ('\0' character is encountered)
        str2[i] = str1[i]; // Copy each character from the first string to the second string
        i++; // Move to the next character in the strings
    }

    // Ensure the second string is NULL terminated
    str2[i] = '\0'; // Add the NULL terminator at the end of the second string

    // Display the first and second strings along with the number of characters copied
    printf("\nThe First string is : %s\n", str1);
    printf("The Second string is : %s\n", str2);
    printf("Number of characters copied : %d\n\n", i);
	
	return 0; // Return 0 to indicate successful execution of the program
}

Output:

Copy one string into another string :                                                                         
-----------------------------------------                                                                     
Input the string : This is a string to be copied.                                                             
                                                                                                              
The First string is : This is a string to be copied.                                                          
                                                                                                              
The Second string is : This is a string to be copied.                                                         
                                                                                                              
Number of characters copied : 31

Flowchart:

Flowchart: Copy one string into another string.

For more Practice: Solve these Related Problems:

Write a C program to copy a string to another using pointer arithmetic without using strcpy().
Write a C program to manually duplicate a string character by character and then print both strings.
Write a C program to copy a string and simultaneously convert all letters to uppercase.
Write a C program to copy a string into a new buffer and then reverse the copied string before displaying it.

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