題目

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

題意

輸入a,b兩個數，輸出兩個數之和注意每三位用逗號隔開。

分析

*if ((i + 1) % 3 == len % 3 && i != len - 1) cout << ",";

程式碼

#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    string s = to_string(a + b);
    int len = s.length();
    for (int i = 0; i < len; i++) {
        cout << s[i];
        if (s[i] == '-') continue;
        if ((i + 1) % 3 == len % 3 && i != len - 1) cout << ",";
    }
    return 0;
}
 

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作者：柳婼 
來源：CSDN 
原文：https://blog.csdn.net/liuchuo/article/details/51985923