计算1 +1！/ X + 2！/ X ^ 2 +…+ N！/ X ^ N

Question

嗨，大家好，我试图用c＃编写一个计算1 + 1！/ X + 2！/ X ^ 2 +…+ N！/ X ^ N的程序，但是给出了错误的结果，我尝试调试它，但是找不到任何人可以出错帮我吗？

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

您需要添加ifac = 1; 在每个循环中。

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);