poj 2562 Primary Arithmetic

#include <cstdio>int main(int argc, char const *argv[]){long long a,b;while(~scanf("%I64d%I64d", &a, &b) && a!=0 || b!=0){if(a<b) {long long tmp = a;a = b; b = tmp;}int ans=0, tmp=0;while(a!=0){if(a%10+b%10+tmp>9){++ans;tmp=1;} else {tmp=0;}a/=10; b/=10;}switch(ans){case 0 : printf("No carry operation.n"); break;case 1 : printf("1 carry operation.n");  break;default: printf("%d carry operations.n", ans);}}return 0;}