用c#计算阶乘

本文关键字：阶乘 计算 | 更新日期: 2023-09-27 18:07:18

我正在尝试编写一个程序，该程序将接受用户输入值并询问他们是否要计算数字1到n的值或n的阶乘!这是我目前看到的

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Project_2_Part_B
{
    class Program
    {
        static void Main(string[] args)
        {
            var Fkeylow = "f";
            var FkeyCap = "F";
            var Skeylow="s";
            var SkeyCap="S";
            int n = 0;
            long factorial = n;
            Console.WriteLine("Input a value n");
            n = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Do you want to calculate factorial or sum");
            Console.WriteLine("Enter F or S");
            var A = Console.ReadLine();
            if (A == Fkeylow)
                Console.WriteLine();
            if (A == FkeyCap)
                Console.WriteLine();
            var B=Console.ReadLine();
            if (B == Skeylow)
                Console.WriteLine();
            if (B == SkeyCap)
                Console.WriteLine();
            Console.WriteLine("Press any key to close...");
            Console.ReadLine();
        }
    }
}

我的问题是计算的语法使代码在n>1时执行n*(n-1)。

用c#计算阶乘

static void Main(string[] args)
{
    Console.WriteLine("Input a value n");
    string number = Console.ReadLine(); // Read number
    int n = Convert.ToInt32(number); // Converting to int
    Console.WriteLine("Do you want to calculate factorial or sum? ");
    Console.WriteLine("Enter F or S. ");
    string choose = Console.ReadLine(); // F or S
    int result = -1; // To view later
    if (choose == "f" || choose == "F")
    {
        result = 1;
        for (int i = n; i >= 1; i--) // Loop for calculating factorial
            result *= i;
    }
    else if (choose == "s" || choose == "S")
    {
        result = 0;
        for (int i = n; i >= 1; i--) // Loop for calculating sum
            result += i;
    }
    Console.WriteLine(result); // Printing answer
    Console.WriteLine("Press any key to close...");
    Console.ReadLine();
}

使用递归是另一种方法:

 static void Main(string[] args)
 {
        int n = 5;
        Console.WriteLine(factorial(n));
        Console.WriteLine(sum(n));
        Console.Read();
 }
 public static int sum(int n)
 {
     if(n==0)
        return 0;
     return n+sum(n-1);
 }
 public static int factorial(int n)
 {
    if (n == 1)
       return 1;
    return n * factorial(n - 1);
 }

打印:

120 -->5!
15  -->1+2+3+4+5

基本解决方案在这里，经过测试，

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication50
{
    class Program
    {
        static void Main(string[] args)
        {
            NumberManipulator manipulator = new NumberManipulator();
            Console.WriteLine("Factorial of six is :" + manipulator.factorial(16));
            Console.ReadLine();
        }
    }
class NumberManipulator
{
    public int factorial(int num)
    {
        int result=1;
        int b = 1;
        do
        {
            result = result * b;//fact has the value 1  as constant and fact into b will be save in fact to multiply again. 
            Console.WriteLine(result);
            b++;
        } while (num >= b);
        return result;
    }
  }
}
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