更优雅的方式选择比特大小和伪随机比特生成

Question

有没有比我在这里做的更优雅的方式来进行位大小选择和伪随机二进制位生成？实际上我需要编写一个算法，让用户控制生成的随机二进制位的位大小（最大 16 位）。这是我写的函数，但我不确定这是否是最小/最优雅的。由于这是科学需要，效率并不重要，但代码的优雅和易于理解确实很重要。那么有没有更有效/更优雅的方式来做同样的事情？

static string randomBit() {
    int bitSize = 0, input = 0;
    Console.Write("Input Bit Size (Maximum is 16 Bit): ");
    input = Convert.ToInt32(Console.ReadLine());
    Random choice = new Random();
    if(input == 0 || input > 16) {
        bitSize = 0;
    }
    else if(input == 1) {
        bitSize = 1;
    }
    else if(input == 2) {
        int randomChoice = choice.Next(2, 3);
        bitSize = randomChoice;
    }
    else if(input == 3) {
        int randomChoice = choice.Next(4, 7);
        bitSize = randomChoice;
    }
    else if(input == 4) {
        int randomChoice = choice.Next(8, 15);
        bitSize = randomChoice;
    }
    else if(input == 5) {
        int randomChoice = choice.Next(16, 31);
        bitSize = randomChoice;
    }
    else if(input == 6) {
        int randomChoice = choice.Next(32, 63);
        bitSize = randomChoice;
    }
    else if(input == 7) {
        int randomChoice = choice.Next(64, 127);
        bitSize = randomChoice;
    }
    else if(input == 8) {
        int randomChoice = choice.Next(128, 255);
        bitSize = randomChoice;
    }
    else if(input == 9) {
        int randomChoice = choice.Next(256, 511);
        bitSize = randomChoice;
    }
    else if(input == 10) {
        int randomChoice = choice.Next(512, 1023);
        bitSize = randomChoice;
    }
    else if(input == 11) {
        int randomChoice = choice.Next(1024, 2047);
        bitSize = randomChoice;
    }
    else if(input == 12) {
        int randomChoice = choice.Next(2047, 4095);
        bitSize = randomChoice;
    }
    else if(input == 13) {
        int randomChoice = choice.Next(4096, 8191);
        bitSize = randomChoice;
    }
    else if(input == 14) {
        int randomChoice = choice.Next(8192, 16383);
        bitSize = randomChoice;
    }
    else if(input == 15) {
        int randomChoice = choice.Next(16384, 32767);
        bitSize = randomChoice;
    }
    else if(input == 16) {
        int randomChoice = choice.Next(32768, 65535);
        bitSize = randomChoice;
    }
    string binary = Convert.ToString(bitSize, 2);
    return binary;
}

同样作为第二个问题，如果我在代码询问位大小时按 Enter 两次，它会返回异常错误。有没有办法绕过相同的？

Answer 1

首先，我真的认为你可以减少 if/else 语句的数量：

private static string randomBit()
{
    int bitSize = 0, input = 0;
    Console.Write("Input Bit Size (Maximum is 16 Bit): ");
    input = Convert.ToInt32(Console.ReadLine());
    Random choice = new Random();

    if (input <= 0 || input > 16)
    {
        bitSize = 0;
    }
    else if(input == 1)
    {
        bitSize = 1;
    }
    else
    {                        
        int randomChoice = choice.Next(1 << (input-1), (1 << input)-1);
        bitSize = randomChoice;
    }

    string binary = Convert.ToString(bitSize, 2);
    return binary;
}

如果您对该表达式中的左移不满意：int randomChoice = choice.Next(1 << (input-1), (1 << input)-1);，并且您对可读性更感兴趣，那么您可以随时将其替换为：

int randomChoice = choice.Next(Math.Pow(2, input - 1), Math.Pow(2, input) - 1);

关于异常的问题，答案是肯定的。您遇到的问题是您没有验证Convert.ToInt32 函数的输入。

你可以写而不是input = Convert.ToInt32(Console.ReadLine());：

do
{
   string inputString = Console.ReadLine();
   if(!Int32.TryParse(inputString, out input))     // will return false if it can't convert
   {
       Console.WriteLine("Please enter a number between 1 and 16!");
       input = 0;
   }
}while(input == 0);