简短的杨辉三角C++实现

注意：需要C++11的支持

一、思想

∵

(kn)=n!k!×(n−k)!

又

(k+1n)=n!(k+1)!×(n−k−1)!

∴

(k+1n)=(kn)×n−kk+1

二、源代码：

#include <iostream>
#include <iomanip>

using namespace std;

int main() {
    auto num = 0;

    cout << "Please input the num:" << endl;
    cin >> num;

    for (auto row = 0; row < num; ++row) {
        auto temp = 1;

        for (auto space = 0; space < num - row; ++space) {
            cout << setw(2) << " ";
        }

        for (auto col = 0; col <= row; ++col) {
            cout << " " << setw(4) << temp;

            temp = temp * (row - col) / (col + 1);
        }
        cout << endl;
    }
    cout << endl;

    return 0;
}