C#如何生成随机数 C# Random类的使用方法和技巧

Random rand = new Random();
int randomNumber = rand.Next();        // 生成一个非负整数
int rangeNumber = rand.Next(1, 101);   // 生成1到100之间的整数（包含1，不包含101）
double doubleNumber = rand.NextDouble(); // 生成0.0到1.0之间的双精度小数（包含0.0，不包含1.0）

// ❌ 错误做法：每次循环都新建Random
for (int i = 0; i < 5; i++)
{
    Random badRand = new Random();
    Console.WriteLine(badRand.Next(1, 10));
}

private static Random globalRand = new Random();
<p>public static int GetRandomNumber(int min, int max)
{
return globalRand.Next(min, max);
}</p>

double randomFloat = rand.NextDouble() * (max - min) + min; // 生成min到max之间的double
<p>// 模拟随机bool
bool randomBool = rand.Next(2) == 1;</p>

public static class RandomExtensions
{
    public static bool NextBool(this Random r) => r.Next(2) == 1;
}
// 使用：
bool flag = rand.NextBool();

private static readonly ThreadLocal<Random> threadRand =
    new ThreadLocal<Random>(() => new Random(Guid.NewGuid().GetHashCode()));

private static readonly Random sharedRand = new Random();
private static readonly object syncLock = new object();
<p>public static int GetThreadSafeRandom(int min, int max)
{
lock (syncLock)
{
return sharedRand.Next(min, max);
}
}</p>