取模乘10
```#include<stdio.h>
int main ()
{
int n=0;
scanf("%d",&n);
int i=0;
int num=0;
int sum=0;
while(n!=0)
{
sum*=10;
num=n%10;
n=n/10;
sum+=num;
}
printf("%d",sum);
return 0;
}