1001 A+B Format-优快云博客

本文介绍了一种解决1001A+B问题的方法，即计算两个整数的和，并以标准格式输出结果，具体为从个位到高位每三位数字使用逗号分隔。通过Java实现，利用字符串操作完成格式化输出，适用于-10^6到10^6范围内的整数加法。

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 −106≤a,b≤106. 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

简单翻译：求两个数的和，将和从个位到高位，每三个数由逗号分隔，负号保留，如：-1001 -> -1,001

解析：主要是求和后转成字符串，用字符串的长度 len%3 判断一下是否等于下标 (i+1)%3，注意末尾没有逗号！

import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in) ;
		int a, b ;
		
		a = input.nextInt() ;
		b = input.nextInt() ;
		
		String sum = Integer.toString(a + b) ;
		
		int i ;
		int len = sum.length() ;

		for(i=0; i<len; i++) {
			System.out.printf("%c", sum.charAt(i)) ;
			if(sum.charAt(i) == '-') continue ;
			if((i + 1) % 3 == len % 3 && i != len - 1) {
				System.out.printf(",") ;
			}
		}
		System.out.println() ;
	}

}