Reverse a String In-Place

Code

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

void reverse_string(char *str) {
    int l = 0, r = strlen(str)-1;

    while (l<r) {
        char tmp = *(str + l);
        *(str + l) = *(str + r);
        *(str + r) = tmp;
        l++;
        r--;
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    int i = 0;
    while (str[i] != '\0') {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    reverse_string(str);
    printf("%s", str);
    return 0;
}

Solving Approach