如何在C#中定义0交叉的值？

using System;
using System.Collections.Generic;

class ZeroCrossingExample
{
    static void Main()
    {
        // 生成一个简单的正弦波信号
        double[] signal = GenerateSineWave(1.0, 100, 0.1);

        // 检测0交叉点
        List<double> zeroCrossings = DetectZeroCrossings(signal);

        // 输出0交叉点的索引
        foreach (double index in zeroCrossings)
        {
            Console.WriteLine("Zero crossing at index: " + index);
        }
    }

    // 生成一个频率为freq，采样点数为numSamples，采样间隔为sampleInterval的正弦波信号
    static double[] GenerateSineWave(double freq, int numSamples, double sampleInterval)
    {
        double[] signal = new double[numSamples];
        for (int i = 0; i < numIndices; i++)
        {
            signal[i] = Math.Sin(2 * Math.PI * freq * i * sampleInterval);
        }
        return signal;
    }

    // 检测信号中的0交叉点
    static List<double> DetectZeroCrossings(double[] signal)
    {
        List<double> zeroCrossings = new List<double>();
        for (int i = 1; i < signal.Length; i++)
        {
            // 如果当前样本和前一个样本异号，则发生了0交叉
            if ((signal[i] > 0 && signal[i - 1] <= 0) || (signal[i] < 0 && signal[i - 1] >= 0))
            {
                zeroCrossings.Add(i);
            }
        }
        return zeroCrossings;
    }
}