C# Programming/Keywords/operator

The operator keyword allows a class to overload arithmetic and cast operators:

public class Complex
{
    private double re, im;
 
    public double Real
    {
        get { return re; }
        set { re = value; }
    }
 
    public double Imaginary
    {
        get { return im; }
        set { im = value; }
    }
 
    // binary operator overloading
    public static Complex operator +(Complex c1, Complex c2)
    {
        return new Complex() { Real = c1.Real + c2.Real, Imaginary = c1.Imaginary + c2.Imaginary };
    }
 
    // unary operator overloading
    public static Complex operator -(Complex c)
    {
        return new Complex() { Real = -c.Real, Imaginary = -c.Imaginary };
    }
 
    // cast operator overloading (both implicit and explicit)
    public static implicit operator double(Complex c)
    {
        // return the modulus: sqrt(x^2 + y^2)
        return Math.Sqrt(Math.Pow(c.Real, 2) + Math.Pow(c.Imaginary, 2));
    }
 
    public static explicit operator string(Complex c)
    {
        // we should be overloading the ToString() method, but this is just a demonstration
        return c.Real.ToString() + " + " + c.Imaginary.ToString() + "i";
    }
}
 
public class StaticDemo
{
    public static void Main()
    {
        Complex number1 = new Complex() { Real = 1, Imaginary = 2 };
        Complex number2 = new Complex() { Real = 4, Imaginary = 10 };
        Complex number3 = number1 + number2; // number3 now has Real = 5, Imaginary = 12
 
        number3 = -number3; // number3 now has Real = -5, Imaginary = -12
        double testNumber = number3; // testNumber will be set to the absolute value of number3
        Console.WriteLine((string)number3); // This will print "-5 + -12i".
        // The cast to string was needed because that was an explicit cast operator.
    }
}

C# Keywords
abstract as base bool break byte case catch char checked class const continue decimal default delegate do double else enum event explicit extern false finally fixed float for foreach goto if implicit in int interface internal is lock long namespace new null object operator out override params private protected public readonly ref return sbyte sealed short sizeof stackalloc static string struct switch this throw true try typeof uint ulong unchecked unsafe ushort using var virtual void volatile while
Special C# Identifiers
add alias get global partial remove set value where yield