C Programs | IT Developer
IT Developer

C Programs

Share with a Friend
Previous
HOME
Next

Strings in C

Reverse string

C Program: Reverse a String (Without strrev())

Method 1: Using gets() function

C 
#include <stdio.h>


 


int main() {


    char str[100], rev[100];


    int i, j, length = 0;


 


    // Input string


    printf("Enter a string: ");


    gets(str); // unsafe, use fgets() in practice


 


    // Find string length


    for (i = 0; str[i] != '\0'; i++) {


        length++;


    }


 


    // Reverse string manually


    for (i = length - 1, j = 0; i >= 0; i--, j++) {


        rev[j] = str[i];


    }


    rev[j] = '\0'; // Null terminate reversed string


 


    // Display reversed string


    printf("Reversed string: %s\n", rev);


 


    return 0;


}

Output

 
INPUT :
Enter a string: ITDeveloper

OUTPUT :
Reversed string: repoleveDTI

Explanation

  1. The program reads a string from the user.
  2. The length of the string is found using a loop.
  3. A second loop copies characters from the end of str to rev.
  4. The reversed string is null-terminated and printed.

 

C Program: Reverse a String (Without strrev())

Method 2: Using fgets() function

C 
#include <stdio.h>


 


int main() {


    char str[100], rev[100];


    int i, j, length = 0;


 


    printf("Enter a string: ");


    fgets(str, sizeof(str), stdin);


 


    // Remove newline character if present


    for (i = 0; str[i] != '\0'; i++) {


        if (str[i] == '\n') {


            str[i] = '\0';


            break;


        }


        length++;


    }


 


    // Reverse the string


    for (i = length - 1, j = 0; i >= 0; i--, j++) {


        rev[j] = str[i];


    }


    rev[j] = '\0';


 


    printf("Reversed string: %s\n", rev);


 


    return 0;


}

Output

 
INPUT :
Enter a string: ITDeveloper

OUTPUT :
Reversed string: repoleveDTI

Explanation

  1. The program reads a string from the user.
  2. The length of the string is found using a loop.
  3. A second loop copies characters from the end of str to rev.
  4. The reversed string is null-terminated and printed.

 

Previous
Next