Reverse a String In-Place

Code

#include <stdio.h>
int str_len(char *str);

void reverse_string(char *str) {
    int res = str_len(str);
    char temp = 0;
    for(int i = 0; i < res/2; i++)
    {
       temp = str[i];
       str[i] = str[res - i - 1];
       str[res - i - 1] = temp;
    }
    // Your logic here
}

int str_len(char *str)
{
    int cnt = 0;
    for(int i = 0; str[i] != '\0'; i++)
    {
        cnt++;
    }
    return cnt;
}
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