C# METHODS

A method is a group of statements that together perform a task. Every C# program has at least one class with a method named Main.

Defining Methods in C#

Following code snippet shows a function FindMax that takes two integer values and returns the larger of the two. It has public access specifier, so it can be accessed from outside the class using an instance of the class

using System;

namespace ConsoleApp1
{
    class Program
    {
        class NumberManipulator
        {
            public int FindMax(int num1, int num2)
            {
                /* local variable declaration */
                int result;
                if (num1 > num2)
                    result = num1;
                else
                    result = num2;
                return result;
            }
            static void Main(string[] args)
            {
                /* local variable definition */
                int a = 100;
                int b = 200;
                int ret;
                NumberManipulator n = new NumberManipulator();
                //calling the FindMax method
                ret = n.FindMax(a, b);
                Console.WriteLine("Max value is : {0}", ret);
                Console.ReadLine();
                //Max value is : 200
            }
        }
    }
}

Recursive Method Call A method can call itself. This is known as recursion. Following is an example that calculates factorial for a given number using a recursive function:

Passing Parameters to a Method

A reference parameter is a reference to a memory location of a variable. When you pass parameters by reference, unlike value parameters, a new storage location is not created for these parameters. The reference parameters represent the same memory location as the actual parameters that are supplied to the method.

//Passing Parameters by Reference
using System;

namespace ConsoleApp1
{
    class NumberManipulator
    {
        public void swap(ref int x, ref int y)
        {
            int temp;
            temp = x; /* save the value of x */
            x = y; /* put y into x */
            y = temp; /* put temp into y */
        }

        static void Main(string[] args)
        {
            NumberManipulator n = new NumberManipulator();
            /* local variable definition */
            int a = 100;
            int b = 200;
            Console.WriteLine("Before swap, value of a : {0}", a);
            Console.WriteLine("Before swap, value of b : {0}", b);
            /* calling a function to swap the values */
            n.swap(ref a, ref b);
            Console.WriteLine("After swap, value of a : {0}", a);
            Console.WriteLine("After swap, value of b : {0}", b);
            Console.ReadLine();
        }
    }
}

A return statement can be used for returning only one value from a function. However, using output parameters, you can return two values from a function. Output parameters are similar to reference parameters, except that they transfer data out of the method rather than into it.