PAT（甲级）1001. A+B Format (20)

题目：https://www.patest.cn/contests/pat-a-practise/1001

代码：#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
using namespace std;
int main()
{
int a,b,sum,i,length=0;
int ans[12];
scanf("%d%d",&a,&b);
sum=a+b;
if(sum<0){
printf("-");
sum=-sum;
}
do{
ans[length++]=(sum%10);
sum=sum/10;
}while(sum!=0);
for(i=length-1;i>=0;i--){
printf("%d",ans[i]);
if(i%3==0&&i>0)
printf(",");
}
system("pause");
}