PAT（甲级）1001 A+B Format (20 分)

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

比较简单的题目，按和的大小分情况输出即可。

#include 
#include 
using namespace std;
int main()
{
	int a, b;
	cin >> a >>  b;
	a = a + b;
	if (a < 0)
	{
		cout << '-';
		a = -a;
	}

	if (a < 1000)
		cout << a << endl;
	else if (a < 1000000)
		cout << a / 1000 << ',' << setw(3) << setfill('0') << a % 1000;
	else
		cout << a / 1000000 << ',' << setw(3) << setfill('0') << a % 1000000 / 1000 <<','<< setw(3) << setfill('0') << a % 1000 << endl;
}