1001.a+b Format_calculate a + b and output the sum in standard for-优快云博客

本文链接：https://blog.youkuaiyun.com/bingeezq/article/details/78512426

本文介绍了一种方法，用于计算两个整数a和b的和，并将结果显示为标准格式，即每三位数字用逗号分隔。文章提供了一个Java实现示例，包括输入输出流程及格式化技巧。

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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

大意：计算a,b之和，每隔3位输出一个“，”。

思路：a,b完成计算后转换为字符数组形式，依次遍历，除了第一位是负号的情况，只要当前位的下标i满足(i + 1) % 3 == len % 3并且i不是最后一位，就在逐位输出的时候在该位输出后的后面加上一个逗号。

代码：

import java.util.Scanner;
public class Main {
  public static void main(String[] args){
    int a,b;
    Scanner in=new Scanner(System.in);
    a=in.nextInt();
    b=in.nextInt();
    String s=String.valueOf(a+b);
    char[] ch=s.toCharArray();
    for(int i=0;i<s.length();i++){
      System.out.printf("%c",ch[i]);
      if(ch[i]=='-')continue;
      if((i+1)%3==s.length()%3&&i!=s.length()-1)
        System.out.printf(",");
}
}
}