0分求助啊大佬们/(ㄒoㄒ)/~~

#include <stdio.h>

int main() {
    int n, a;
    int sum;
    scanf("%d", &n);
    if (n < 0) {
        n = -n;
        printf("-");
    }
    if (n % 10 == 0) {
        n = n / 10;
    }
    while (n != 0) {
        a = n % 10;
        n = n / 10;
        sum = sum * 10 + a;
    }
    printf("%d", sum);
    return 0;
}