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 
using namespace std;
 int num[111],cnt=0; 
int main()
{
    int x,y,i,j;
    while(cin>>x>>y)
    {        int ans=x+y;
       // cout<=0;cnt--)
        {
            cout<