Reverse a String In-Place

Code

#include <stdio.h>

void reverse_string(char *str) {
    int idx=0;
    char t;
    while(str[idx]!='\0'){idx++;}
    int end=idx;
    {       
        for (int i=0;i<(end/2);i++){
            t=str[i];
            str[i]=str[--idx];
            str[idx]=t;
        }
    }
}

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