PAT甲级 1001 A+B Format

题目链接：https://pintia.cn/problem-sets/994805342720868352/problems/994805528788582400

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

AC代码：

 #include <iostream>
 #include<cstdio>
 using namespace std;
 int main(int argc, char const *argv[])
 {
     int a, b;
     cin >> a >> b;

     int c = a + b;
     if (a + b < ) {
         cout << "-";
         c = -c;
     }
     if (c >= ) {
         printf("%d,%03d,%03d\n", c / , c %  / , c %  );

     } else if (c >= ) {
         printf("%d,%03d\n", c / , c % );
     } else {
         printf("%d\n", c );
     }

     return ;
 }