1001. A+B Format (20) ——PAT (Advanced Level) Practise

题目信息：

1001. A+B Format (20)

时间限制 400 ms

内存限制 32000 kB

代码长度限制 16000 B

判题程序 Standard 作者 CHEN, Yue

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

Each input file contains one test case. Each case contains a pair of integers a and b where -1000000 <= a, b <= 1000000. The numbers are separated by a space.

Output

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      

代码如下：

#include <stdio.h>
int main()
{
	int a, b;
	char arr[30], flag;
	arr[29] = '\0';
	while (scanf("%d%d", &a, &b) != EOF)
	{
		int k = 29;
		int s = a + b, t = 0;
		flag = 0;
		if (s < 0)
		{
			flag = 1;
			s *= -1;
		}
		if (s == 0)
			arr[--k] = '0';
		while (s)
		{
			arr[--k] =  '0' + s % 10;
			if (++t == 3)
			{
				t = 0;
				if (s >= 10)
					arr[--k] = ',';
			}
			s /= 10;
		}
		if (flag)
			arr[--k] = '-';
		printf("%s\n", arr + k);
	}
	return 0;
}