Reverse a String In-Place

#include <stdio.h>

void reverse_string(char *str) {
    int left = 0;
    int right = 0;
    char temp;

    while (str[right] != '\0') {
        right++;
    }
    right--;

    while (left < right) {
        temp = str[left];
        str[left] = str[right];
        str[right] = temp;
        left++;
        right--;
    }
}

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

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

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