Question

我正在尝试用c ++创建一个程序，它接受用户输入并显示Pascal三角形的特定行。即输入3应该导致1 3 3 1。但是当我在程序中输入3时，显示“1 1 1 1”。我认为我相当接近，但我无法弄清楚出了什么问题。

#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

将您的代码修改为此..希望这会有所帮助

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

}

当您在for循环中声明k时，此值不是全局的。

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

显示Pascal三角形的第n行

1 个答案: