Question

i have written a program to reverse a string.. But it is not working.. It is printing the same string which is scanned.. What is the problem with the code?

#include <stdio.h>
#include <stdlib.h>
char *strrev(char *s)
{
        char *temp = s;
        char *result = s;
        char t;
        int l = 0, i;
        while (*temp) {
                l++;
                temp++;
        }
        temp--;
        for (i = 0; i < l; i++) {
                t = *temp;
                *temp = *s;
                *s = t;
                s++;
                temp--;
        }
        return result;
}

int main()
{
        char *str;
        str = malloc(50);
        printf("Enter a string: ");
        scanf("%s", str);
        printf("%s\n\n", strrev(str));
        return 0;
}

Answer 1

for (i = 0; i < l; i++)

You’re walking through the entire string, so you’re reversing it twice – it won’t be reversed after all. Walk only halfways:

for (i = 0; i < l / 2; i++)

Also, try using int len = strlen() instead of the while-not-end-of-string loop, if you’re permitted to do so.