PAT (Advanced Level) 1001 A+B Format

1001 A+B Format （20 分）
Calculate a+b and output the sum in standard format -- that is, the digits must be separated into groups of three by commas (unless there are less than four digits).
Input Specification:
Each input file contains one test case. Each case contains a pair of integers a and b where −10​6​​≤a,b≤10​6​​. The numbers are separated by a space
Output Specification:
For each test case, you should output the sum of a and b in one line. The sum must be written in the standard format.
Sample Input:
-1000000 9
Sample Output:
-999,991

#include<bits/stdc++.h> 
using namespace std;
 int num[111],cnt=0; 
int main()
{
    int x,y,i,j;
    while(cin>>x>>y)
    {        int ans=x+y;
       // cout<<ans<<endl;
       if(ans==0)
       {
           puts("0");
           continue;
       }
        cnt=0;
        if(ans<0)
        {
            cout<<"-";
            ans=-ans;
        }
         while(ans)
        {
            num[cnt++]=ans%10;
            ans/=10;
        }
        int tmp = cnt%3;
        cnt--;
        for(i=0;i<tmp;i++,cnt--)
        {
            cout<<num[cnt];
        }
        //cout<<cnt<<endl;
        if(cnt==-1)
            puts("");
        else if(tmp)
            cout<<",";
        int tcnt=0;
        for(;cnt>=0;cnt--)
        {
            cout<<num[cnt];
            tcnt++;
            if(cnt==0)
            {
                puts("");
                break;
            }
            if(tcnt==3)
            {
                cout<<",";
                tcnt=0;
            }
        }
       // puts("");
    }
}