在C＃中计算阶乘因子

我正在尝试编写一个程序，该程序将获取用户输入值，并询问他们是否要计算1到n的数字值或n的阶乘值！这是我迄今为止在C＃中计算阶乘因子

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(); 
     } 
    } 
}

我的问题是用计算的语法，以使代码执行N *（N-1），而N> 1 任何帮助将不胜感激。先进的谢谢！

来源

2011-09-03 Thomas

HTTP：//en.wikipedia。 org/wiki/Factorial –

@Stephen你的意思是：input = 10 - > print 10！那么9！那么...... 1！？ – 2011-09-03 04:58:26

像用户输入5然后按“f”因数输出应该是120.（5x4x3x2x1） – Thomas

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(); 
}

如果答案对您有帮助，请不要忘记标记为最佳答案。

来源

2011-09-03 04:55:48

我总是过于复杂的事情。非常感谢你的帮助！ – Thomas

使用递归是做它的另一种方式：

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

来源

2011-09-03 05:11:14 Icarus

@lcarus他看起来像begginer，不能理解递归解决方案 – 2011-09-03 05:12:54

@DDD你去了，他不喜欢递归的版本。真是太遗憾了：'（ – Icarus

我很确定“Project_2_Part_B”是作为初学者的免费赠品;） –

，基本解决方案是在这里，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; 
    } 
    } 
}

来源

2014-11-16 03:58:15 casillas

在C＃中计算阶乘因子

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