Calling members of another class

//calling methods of another class by creating object

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CSharpConsole
{
    class Testclasses
    {
        static void Main()
        {
            Method_ex m1= new Method_ex();     // m1 is a object created
            Params p1=new Params();            // p1 is a object created
            m1.Test1();                        // calling methods
            m1.Test2(6, 12);
            Console.WriteLine(m1.Test3());
            Console.WriteLine(m1.Test4("Hello"));
            p1.AddNums(100, 75, 50);

            int x = 0, y = 0;
            p1.Math1(100, 25, ref x, ref y);
            Console.WriteLine(x + "   " + y);
            p1.Math2(100, 50, out x, out y);
            Console.WriteLine(x+ "   "+y);
            Console.ReadLine();              // waiting to key press
        }

    }
}

Operator Overloading

// Write a prorram to print the sum of complex numbers


using System;

public struct Complex
{
    public int real;
    public int imaginary;

    public Complex(int real, int imaginary)
    {
        this.real = real;
        this.imaginary = imaginary;
    }

    // Declare which operator to overload (+), the types 
    // that can be added (two Complex objects), and the 
    // return type (Complex):
    public static Complex operator +(Complex c1, Complex c2)
    {
        return new Complex(c1.real + c2.real, c1.imaginary + c2.imaginary);
    }
    // Override the ToString method to display an complex number in the suitable format:
    public override string ToString()
    {
        return (String.Format("{0} + {1}i", real, imaginary));
    }

    public static void Main()
    {
        Complex num1 = new Complex(2, 3);
        Complex num2 = new Complex(3, 4);

        // Add two Complex objects (num1 and num2) through the
        // overloaded plus operator:
        Complex sum = num1 + num2;

        // Print the numbers and the sum using the overriden ToString method:
        Console.WriteLine("First complex number:  {0}", num1);
        Console.WriteLine("Second complex number: {0}", num2);
        Console.WriteLine("The sum of the two numbers: {0}", sum);
        Console.ReadKey();

    }
}

Parameters in CSharp

      Parameters are defined so that the methods can be made more dynamic. Parameters of a methods can be of 2 types.

•  Input parameters.

• Output parameters.

       Input parameters are used for bringing values in the method for execution. Whereas output parameters are used for carrying a value ouut of the method after execution of the method

       By default every parameter we pass to a method is an input parameter and if we want to define a parameter as output parameter we need to prefix the parameter with ref or out keyword.

      public void test (int x,ref int y,out int z)

       Here x is an input parameter and y& z are output parameters.

Note: By using return types also we can send results out of a method, but only a single result whereas if we are sending results out of a method using output parameters we have a chance of sending more than 1 result at the time of execution.