定义复数的类，并实现复数的输入输出。设计三个方法分别完成复数的加、减和乘法运算（用c#语言）

在C#中，我们可以定义一个名为`ComplexNumber`的类来表示复数，并包含两个私有成员变量：实部`real`和虚部`imaginary`。这里是一个简单的实现：

public class ComplexNumber
{
    private double real;
    private double imaginary;

    // 构造函数用于初始化复数
    public ComplexNumber(double realPart, double imaginaryPart)
    {
        this.real = realPart;
        this.imaginary = imaginaryPart;
    }

    // 输入输出方法
    public override string ToString()
    {
        return $"({real}, {imaginary})";
    }

    // 读取输入方法，假设从控制台获取用户输入
    public static ComplexNumber FromUserInput(string input)
    {
        string[] parts = input.Split(',');
        return new ComplexNumber(double.Parse(parts[0]), double.Parse(parts[1]));
    }

    // 复数加法
    public ComplexNumber Add(ComplexNumber other)
    {
        double realSum = this.real + other.real;
        double imaginarySum = this.imaginary + other.imaginary;
        return new ComplexNumber(realSum, imaginarySum);
    }

    // 复数减法
    public ComplexNumber Subtract(ComplexNumber other)
    {
        double realDiff = this.real - other.real;
        double imaginaryDiff = this.imaginary - other.imaginary;
        return new ComplexNumber(realDiff, imaginaryDiff);
    }

    // 复数乘法
    public ComplexNumber Multiply(ComplexNumber other)
    {
        double realProduct = this.real * other.real - this.imaginary * other.imaginary;
        double imaginaryProduct = this.real * other.imaginary + this.imaginary * other.real;
        return new ComplexNumber(realProduct, imaginaryProduct);
    }
}

你可以像下面这样使用这个类：

public static void Main(string[] args)
{
    Console.Write("请输入第一个复数 (a, b): ");
    string input1 = Console.ReadLine();
    ComplexNumber num1 = ComplexNumber.FromUserInput(input1);

    Console.Write("请输入第二个复数 (c, d): ");
    string input2 = Console.ReadLine();
    ComplexNumber num2 = ComplexNumber.FromUserInput(input2);

    ComplexNumber sum = num1.Add(num2);
    ComplexNumber difference = num1.Subtract(num2);
    ComplexNumber product = num1.Multiply(num2);

    Console.WriteLine($"加法结果: {sum}");
    Console.WriteLine($"减法结果: {difference}");
    Console.WriteLine($"乘法结果: {product}");
}