c++ - 显示帕斯卡三角形的第 n 行

Question

我正在尝试用 C++ 创建一个程序，在其中接受用户输入并显示 Pascal 三角形的特定行。即输入 3 应该得到 1 3 3 1。但是，当我在我的程序中输入 3 时，它显示“1 1 1 1”。我想我已经很接近了，但我不太清楚哪里出了问题。

#include <iostream>
using namespace std;
int n, k, fact1, fact2, fact3, number1, number2, number3, nTakeAwayK, nChooseK;

void CalculateNChooseK();

int main()
{
    cout << "Enter a row number for Pascal's Triangle: ";
    cin >> n;
    int x = 1;
    for (int k = 0; k <= n; k++)
    {
        cout << x << '\t';
        CalculateNChooseK();
        x = nChooseK;

    }
    cout << endl;
    system("PAUSE");
    return 0;
}

void CalculateNChooseK()
{
    fact1 = 1;
    for (number1 = 1; number1 <= n; number1++)
    {
        fact1 = (fact1 * number1);
    }

    fact2 = 1;
    for (number2 = 1; number2 <= k; number2++)
    {
        fact2 = (fact2 * number2);
    }

    nTakeAwayK = (n - k);
    fact3 = 1;
    for (number3 = 1; number3 <= nTakeAwayK; number3++)
    {
        fact3 = (fact3 * number3);
    }

    nChooseK = fact1 / (fact2*fact3);
}

Answer 1

修改你的代码..希望这会有所帮助

for (k = 1; k <= n+1; k++)
{
    cout << x << '\t';
    CalculateNChooseK();
    x = nChooseK;

}

当你在 for 循环中声明 k 时，这个值不是全局的。

for (int k = 0; k <= n; k++) // don't declare k here.. and also loop from 1 to n+1 inclusive