第三题
#include <stdio.h>
int main() {
int num ;
printf("请输入一个三位数:\n");
scanf("%d", &num);
int a = num % 10;
int b = num / 10 % 10;
int c = num / 100;
int sum = a * 100 + b * 10 + c;
int sums=a+b+c;
printf("该三位数的逆序数是:%d\n", sum); return 0; }