Reverse a String In-Place

#include <stdio.h>

void reverse_string(char *str) {
    // Your logic here
    char *p = str;
    int str_len = 0;
    while(*p != '\0'){
        str_len++;
        p++;
    }
    int r = str_len - 1;
    for(int l = 0; l < r; l++, r--){
        char sub = str[l];
        str[l] = str[r];
        str[r] = sub;
    }
}

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;
}