计算1 + 1!/ X + 2!/ X ^ 2 + ... + N!/ X ^ N.

Question

嗨伙计们我试图在c#中制作一个程序计算1 + 1!/ X + 2!/ X ^ 2 + ... + N!/ X ^ N但是它给出了错误的结果我试过调试它但是找不到错误可以任何人帮助我吗？

Console.WriteLine("Calculate 1 + 1!/X + 2!/X^2 + … + N!/X^N");
    Console.Write("N:");
    double n = double.Parse(Console.ReadLine());
    Console.Write("X:");
    double x = double.Parse(Console.ReadLine());
    double result = 1;
    int ifac = 1;
    for (int i = 1; i <= n; i++)
    {
        for (int j = i; j >= 1; j--)
        {
            ifac *= j;
        }
        result += ifac / Math.Pow(x, i);
    }
    Console.WriteLine(result);

Answer 1

您需要ifac = 1;在每个循环中添加.

Console.WriteLine("Calculate 1 + 1!/X + 2!/X^2 + … + N!/X^N");
Console.Write("N:");
double n = double.Parse(Console.ReadLine());
Console.Write("X:");
double x = double.Parse(Console.ReadLine());
double result = 1;
int ifac = 1;
for (int i = 1; i <= n; i++)
{
    ifac = 1; //This line is very important
    for (int j = i; j >= 1; j--)
    {
        ifac *= j;
    }
    result += ifac / Math.Pow(x, i);
}
Console.WriteLine(result);