PAT_A 1001 A+B Format

PAT_A 1001 A+B Format

分析

本题需要将A+B的结果转换为由 , 分割的数字，即从个位向前，每输出三个数字就需要一个 , 分割，若没有数字则不输出, ；若错误的话，可以多输入几个数字看一下。

题目的描述

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 \(−10^6≤a,\ b≤10^6\). 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

AC的代码

#include<bits/stdc++.h>

using namespace std;

int main(){
    long long a,b;
    cin>>a>>b;
    a+=b;
    if(a<0){
        cout<<'-';
        a=-a;
    }
    string as = to_string (a);
    b = as.length()%3;
    for(int i=0;i<as.length();i++){
        if(!b){
            if(i)cout<<',';
            b=2;
        }
        else {
            b--;
        }
        cout<<as[i];
    }
    cout<<endl;
    return 0;
}