题解 | #添加逗号#

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

// 先声明函数原型
string formatNumberWithCommas(int n);

int main() {
    int n;
    cin >> n;

    string result = formatNumberWithCommas(n);
    cout << result << endl;

    return 0;
}

// 在主函数后面定义函数
string formatNumberWithCommas(int n) {
    string numStr = to_string(n);
    int len = numStr.length();

    // We will insert commas from right to left
    for (int i = len - 3; i > 0; i -= 3) {
        numStr.insert(i, ",");
    }

    return numStr;
}

#C++#