如何在C#中生成随机整数?


当前回答

为什么不使用int randomNumber=Random.Range(start_Range,end_Range)?

其他回答

Random random = new Random ();
int randomNumber = random.Next (lowerBound,upperBound);

如果您希望CSRNG生成最小值和最大值之间的随机数,这是适合您的。它将使用安全的随机种子初始化随机类。

    class SecureRandom : Random
    {
        public static byte[] GetBytes(ulong length)
        {
            RNGCryptoServiceProvider RNG = new RNGCryptoServiceProvider();
            byte[] bytes = new byte[length];
            RNG.GetBytes(bytes);
            RNG.Dispose();
            return bytes;
        }
        public SecureRandom() : base(BitConverter.ToInt32(GetBytes(4), 0))
        {

        }
        public int GetRandomInt(int min, int max)
        {
            int treashold = max - min;
            if(treashold != Math.Abs(treashold))
            {
                throw new ArithmeticException("The minimum value can't exceed the maximum value!");
            }
            if (treashold == 0)
            {
                throw new ArithmeticException("The minimum value can't be the same as the maximum value!");
            }
            return min + (Next() % treashold);
        }
        public static int GetRandomIntStatic(int min, int max)
        {
            int treashold = max - min;
            if (treashold != Math.Abs(treashold))
            {
                throw new ArithmeticException("The minimum value can't exceed the maximum value!");
            }
            if(treashold == 0)
            {
                throw new ArithmeticException("The minimum value can't be the same as the maximum value!");
            }
            return min + (BitConverter.ToInt32(GetBytes(4), 0) % treashold);
        }
    }

对于强随机种子,我总是使用CryptoRNG而不是时间。

using System;
using System.Security.Cryptography;

public class Program
{
    public static void Main()
    {
        var random = new Random(GetSeed());
        Console.WriteLine(random.Next());
    }

    public static int GetSeed() 
    {
        using (var rng = new RNGCryptoServiceProvider())
        {
            var intBytes = new byte[4];
            rng.GetBytes(intBytes);
            return BitConverter.ToInt32(intBytes, 0);
        }
    }
}
Random r=new Random();
int Numbers=r.next(min value, max value);

从这里修改答案。

如果您可以访问与Intel Secure Key兼容的CPU,则可以使用以下库生成真正的随机数和字符串:https://github.com/JebteK/RdRand和https://www.rdrand.com/

只需从这里下载最新版本,包括Jebtek.RdRand并为其添加一个using语句。然后,您需要做的就是:

// Check to see if this is a compatible CPU
bool isAvailable = RdRandom.GeneratorAvailable();

// Generate 10 random characters
string key       = RdRandom.GenerateKey(10);

 // Generate 64 random characters, useful for API keys 
string apiKey    = RdRandom.GenerateAPIKey();

// Generate an array of 10 random bytes
byte[] b         = RdRandom.GenerateBytes(10);

// Generate a random unsigned int
uint i           = RdRandom.GenerateUnsignedInt();

如果您没有兼容的CPU来执行代码,只需使用rdrand.com上的RESTful服务即可。使用项目中包含的RdRandom包装库,您只需要这样做(注册时可以获得1000个免费调用):

string ret = Randomizer.GenerateKey(<length>, "<key>");
uint ret   = Randomizer.GenerateUInt("<key>");
byte[] ret = Randomizer.GenerateBytes(<length>, "<key>");