1001 A+B Format

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 −. 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

 

题意以及思路：主要就是读入A，B相加之后，调整格式再输出的问题，用string比较好处理，可以考虑每三个数为一个分界，注意判断边界......

 

#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<map>
using namespace std;
int main()
{
    int a,b,sum;
    cin>>a>>b;
    sum=a+b;
    string str;
    str=to_string(sum);
    for(int i=0;i<str.size();i++)
    {
        if((str.size()-i-1)%3==0&&str[i]!='-'&&i!=str.size()-1)
            cout<<str[i]<<",";
        else
            cout<<str[i];
    }
    return 0;
}