题解 | #反向输出一个四位数#

#include <stdio.h>

int main() {
    int n;
    int a, b, c, d;
    int sum = 0,flag = 1000;
    scanf("%d",&n);
        // a = (n % 10)*1000;
        // b = (n%100/10)*100;
        // c = (n/100%10)*10;
        // d = n/1000;
    while (n / 10 > 0 || n > 0) {
        sum+=n%10*flag;
        n = n/10;
        flag/=10;
    }

    printf("%04d",sum);
    return 0;
}