1001. A+B Format (20)-优快云博客

本文介绍了一个简单的C++程序，该程序接收两个整数作为输入，并以标准格式输出它们的和，即每三位数字用逗号分隔。文章通过使用字符数组和条件判断实现了不同长度数字的正确格式化。

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

天天进步：
1、sprintf(str,”%d”,c);用来将int型转换成对应的字符串类型，但是此处是打印到字符数组str中去，记得包含头文件#include

#include <iostream>
#include <string>
#include<cstring>
#include<vector>
using namespace std;

int main () {

char str[10];
int a,b,c;
cin>>a>>b;
c=a+b;
sprintf(str,"%d",c);
int len=strlen(str);
if(str[0]=='-') len-=1;
if(len<=3) cout<<str;
else if(len>3&&len<=6) 
  {
    if(str[0]=='-')
    {
        for(int i=0;i<len+1;i++)
        {
            if(i==len-3) cout<<str[i]<<",";
            else cout<<str[i];
        }
    }
    else
    {
        for(int i=0;i<len;i++)
        {
            if(i==len-4) cout<<str[i]<<",";
            else cout<<str[i];
        }
    }
  }
  else 
  {
    if(str[0]=='-')
    {
        for(int i=0;i<len+1;i++)
        {
            if(i==len-3||i==len-6) cout<<str[i]<<",";
            else cout<<str[i];
        }
    }
    else
    {
        for(int i=0;i<len;i++)
        {
            if(i==len-4||i==len-7) cout<<str[i]<<",";
            else cout<<str[i];
        }
    }
  }
  return 0;
}