// Exercise 3g from Lecture 3

using System;

public class Tester {

  public struct Complex {
    // explicit fields:
    // public int Real;
    // public int Imag;

    // automatic properties:
    public int Real { get ; set ; }
    public int Imag { get ; set ; }
    
    public Complex (int r, int i) {
      this.Real = r;
      this.Imag = i;
    }
    public override string ToString() {
      return this.Real.ToString()+"+"+this.Imag.ToString()+"i";
    }

    public static int sqr (int x) { 
      return x*x;
    }
  
    public static Complex operator+ (Complex a, Complex b) 
    {
      return new Complex(a.Real + b.Real, a.Imag + b.Imag); 
    }
    public static Complex operator- (Complex a, Complex b) 
    {
      return new Complex(a.Real - b.Real, a.Imag - b.Imag); 
    }
    public static Complex operator* (Complex a, Complex b) 
    {
      return new Complex(a.Real*b.Real - a.Imag*b.Imag, a.Real*b.Imag + a.Imag*b.Real); 
    }
    public static Complex operator/ (Complex a, Complex b) 
    {
      return new Complex(a.Imag*b.Real - a.Real*b.Imag, sqr(b.Real) + sqr(b.Imag)); 
    }
  }

  public static void Main (string []args) {
     if (args.Length != 4) { // expect 4 args: r1 i1 r2 i2
       System.Console.WriteLine("Usage: exercise4f <int> <int> <int> <int>");
     } else {
       int r1 = Convert.ToInt32(args[0]);
       int i1 = Convert.ToInt32(args[1]);
       int r2 = Convert.ToInt32(args[2]);
       int i2 = Convert.ToInt32(args[3]);
       Complex c1 = new Complex(r1,i1);
       Complex c2 = new Complex(r2,i2);
       System.Console.WriteLine("Complex addition: {0} + {1} = {2}", c1, c2, c1+c2);
       System.Console.WriteLine("Complex subtraction: {0} - {1} = {2}", c1, c2, c1-c2);
       System.Console.WriteLine("Complex multiplication: {0} * {1} = {2}", c1, c2, c1*c2);
       System.Console.WriteLine("Complex division: {0} / {1} = {2}", c1, c2, c1/c2);
     }
  }

}