我如何创建随机数？

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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：msdn.microsoft/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： msdn.microsoft/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： en.wikipedia/ 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）： msdn.microsoft/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: msdn.microsoft/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: msdn.microsoft/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: en.wikipedia/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): msdn.microsoft/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; } }