A-1001 A+B Format (20 分)

A-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 <string>
#include <iostream>
using namespace std;

int main(){
    int a,b,sum,i,j;
    int str[15]={};
    cin >> a >> b;
    sum=a+b;
    if(sum==0)cout << sum;
    if(sum<0){
        cout<<"-";
        sum=-sum;
    }
    for(i=1;sum>0;i++){//将每一位数字存入数组中
        str[i]=sum%10;
        sum/=10;
    }
    for(j=i-1;j>=1;j--){
        cout << str[j];
        if(j%3==1&&j>1)cout << ",";
    }
    return 0;
}