C Program for Reverse String

In the world of computer programming, manipulating strings is a fundamental skill that every programmer must master. One common task in String manipulation is reversing a String, a process where characters of strings are re-arranged in reverse order. In this article, we will explore various methods to write a C program for reverse string.

Reverse String by Using Array

The most straightforward method for reverse string involves the use of a temporary array to store the reverse string. Let’s write a C program for a reverse string by using an array.

#include <stdio.h>
#include <string.h>
void reverseString(char *str)
{
    int length = strlen(str);
    char temp[length];
    for (int i = 0; i < length; i++)
    {
        temp[i] = str[length - 1 - i];
    }
    // Copy reverse String in the original string
    strcpy(str, temp);
}
void main()
{
    char string[] = "Original String";
    printf("Original string = %s\n", string);
    reverseString(string);
    printf("Reverse string = %s\n", string);
}

Output

Reverse String by using in-place Reversal

For situations where memory efficiency is crucial, we can use in-place reversal to reverse a string. In this method, we swap characters from the beginning and end of the string and move toward the center. Let’s write a C program to reverse a string by using in-place reversal.

#include <stdio.h>
#include <string.h>
void reverseString(char *str)
{
    int end = strlen(str) - 1;
    int start = 0;
    while (start < end)
    {
        char temp = str[start];
        str[start] = str[end];
        str[end] = temp;
        start++;
        end--;
    }
}

void main()
{
    char string[] = "Original String";
    printf("Original string = %s\n", string);
    reverseString(string);
    printf("Reverse string = %s\n", string);
}

Output

The in-place method for string reversal uses a two-pointer system to swap characters, progressively moving towards the center of the sring.

Happy Coding

See Also

• Binary to Decimal Conversion in C
• Decimal to Binary Conversion in C