我如何创建随机数？ [英] How Can I create Random Numbers?

问题描述

如何创建4位随机数字？不使用结构循环和结构条件（例如Loop for，while，if，...）并且不使用Timer

此程序的结果如此程序：



4位数生成必须不同，例如，如果返回1111为假。但结果1234是真的。

How can I create 4-digit Random Numbers? without use Structural Loops and Structural condition (for example Loop for,while,if,...) and without use from Timer
result of this program like this program:

4-digit Produced Must different for example if return 1111 is false. but result 1234 is true.

static void Main(string[] args)
       {
           Random Item = new Random();

           int Num1, Num2, Num3, Num4;
           do
           {
               Num1 = Item.Next(0, 10);
               Num2 = Item.Next(0, 10);
               Num3 = Item.Next(0, 10);
               Num4 = Item.Next(0, 10);

           } while (Num1 == Num2 || Num1 == Num3 || Num1 == Num4 || Num2 == Num3 || Num2 == Num4 || Num3 == Num4);

           Console.WriteLine("{0}{1}{2}{3}", Num1, Num2, Num3, Num4);
           Console.ReadKey();
       }

推荐答案

请参阅：https://msdn.microsoft.com/en-us/library/system.random%28v=vs.110%29.aspx [ ^ ]。



不要犯常见错误，创建 System.Random 的实例几次。记住，算法伪randon 。要随机化，请始终使用种子：

https://msdn.microsoft.com/en-us/library/ctssatww%28v=vs.110%29.aspx [ ^ ]。



从上面引用的文章中显示的代码示例中可以看到，您可以使用 System.DateTime.Now 进行种子设定。要了解为什么需要播种以及伪随机算法如何为您提供随机数，请参阅： https://en.wikipedia.org/ wiki / Pseudorandom_number_generator [ ^ ]。



创建 System.Random 的实例后，重复使用它以满足您的所有需求，只需一个实例。在你的情况下，所有其他调用应该是 System.Random（int，int）：

https://msdn.microsoft.com/en-us/library/2dx6wyd4（v = vs.110）的.aspx [ ^ ]。







警告！参数名称确实具有误导性。 minValue 确实是最小值，但 maxValue 并不是最大值;文档称之为独占上限，这意味着实际最大值为 maxValue - 1 。 :-)

另请参阅返回值部分中的注释。



[END EDIT]



你的无循环简直荒谬。好吧，将调用编码为 Random.Next 100次以获得100个数字，但我怀疑是否有人会这么疯狂。

-SA

Please see: https://msdn.microsoft.com/en-us/library/system.random%28v=vs.110%29.aspx[^].

Don't make a common mistake, creating the instance of System.Random several times. Remember, the algorithm pseudo-randon. To randomize of, always use the seed:
https://msdn.microsoft.com/en-us/library/ctssatww%28v=vs.110%29.aspx[^].

As you can see from the code sample shown in the article referenced above, you can use System.DateTime.Now for seeding. To understand why seeding is needed and how pseudo-random algorithm gives you random numbers, please see: https://en.wikipedia.org/wiki/Pseudorandom_number_generator[^].

After you create your instance of System.Random, reuse it for all your needs, just one instance. In your case, all other calls should be to System.Random(int, int):
https://msdn.microsoft.com/en-us/library/2dx6wyd4(v=vs.110).aspx[^].



Warning! The parameter names are really misleading. minValue is really the minimum, but maxValue is not really maximum; the documentation calls it "exclusive upper bound", which means that real maximum is maxValue − 1. :-)
See also the notes in Return value section.

[END EDIT]

Your "without loops" is simply an absurd. Okay, code the calls to Random.Next 100 times to get 100 numbers, but I doubt anyone would be so insane.

—SA

有类似的东西，你没有任何可见的循环或条件（假设，你想生成一个4位数字）：

With something like that, you don't have any "visible" loop or condition (assuming, you want to generate a single 4 digits number):

class FourRandomDigits
{
	public static string Run()
	{
	    var generator = new FourRandomDigits();
	    return generator.DoRun();
	}

        private static Random rand = new Random();
	private int[] digits = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
	private int remainingCount = 10;
	
	private string DoRun()
	{
	    var builder = new StringBuilder();
	    builder.Append(PickOneDigit());
	    builder.Append(PickOneDigit());
	    builder.Append(PickOneDigit());
	    builder.Append(PickOneDigit());
	    return builder.ToString();
	}
	
	private int PickOneDigit()
	{
	    int index = rand.Next(remainingCount);
	    int result = digits[index];
	    digits[index] = digits[--remainingCount];
	    return result;
	}
}

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