using System;

public class Program

{

    public static void Main()

    {

        ///////////////

        ///// 1. The following example demonstrates if statement in C#

        ///////////////

        IfStatement();

        //////////////

        ///// 2. The following example demonstrates if else statement in C#

        ///////////////

        IfElseStatement();

        ///////////////

        ///// 3. The following example demonstrates if else ... if else statement in C#

        ///////////////

        IfElseIfElseStatement();

        ///////////////

        ///// 4. The following example demonstrates nested if else statement in C#

        ///////////////

        NestedIfElseStatement();

        ///////////////

        ///// 5. The following example demonstrates switch case statement in C#

        ///////////////

        SwitchCaseStatement();

        ///////////////

        ///// 6. The following example demonstrates nested switch case statement in C#

        ///////////////

        NestedSwitchCaseStatement();

    }

    ///////////////

    ///// 1. The following example demonstrates if statement in C#

    ///////////////

    public static void IfStatement()

    {

         Console.WriteLine("-----------If statement-----------");

         // Local variables

         int a = 15;

         // Check the boolean condition using if statement

         if (a < 20) {

            // if condition is true then print the following

            Console.WriteLine("Value of a is less than 20");

         }

         Console.WriteLine("Value of a is : {0}", a);

    }

    ///////////////

    ///// 2. The following example demonstrates if else statement in C#

    ///////////////

    public static void IfElseStatement()

    {

         Console.WriteLine("-----------If else statement-----------");

         // Local variable

         int a = 50;

         // Check the boolean condition

         if (a < 20) {

            // If condition is true then print the following

            Console.WriteLine("Value of a is less than 20");

         } else {

            // Ef condition is false then print the following

            Console.WriteLine("Value of a is not less than 20");

         }

         Console.WriteLine("Value of a is : {0}", a);

    }

    ///////////////

    ///// 3. The following example demonstrates if else ... if else statement in C#

    ///////////////

    public static void IfElseIfElseStatement()

    {

         Console.WriteLine("-----------If else ... If else statement-----------");

         // Local variable

         int a = 50;

         // Check the boolean condition

         if (a == 10) {

            // if condition is true then print the following

            Console.WriteLine("Value of a is 10");

         } 

         else if (a == 20) {

             // if else if condition is true

            Console.WriteLine("Value of a is 20");

         } 

         else if (a == 30) {

            // if else if condition is true

            Console.WriteLine("Value of a is 30");

         } else {

            // if none of the conditions is true

            Console.WriteLine("None of the values is matching");

         }

         Console.WriteLine("Exact value of a is: {0}", a);

    }

    ///////////////

    ///// 4. The following example demonstrates nested if else statement in C#

    ///////////////

    public static void NestedIfElseStatement()

    {

         Console.WriteLine("-----------Nested if else statement-----------");

         // Local variable

         int a = 150;

         int b = 200;

         // Check the boolean condition

         if (a == 100) {

            // if condition is true then check the following

            if (b == 200) {

               // if condition is true then print the following

               Console.WriteLine("Value of a is 100 and b is 200");

            }

         }

         Console.WriteLine("Exact value of a is : {0}", a);

         Console.WriteLine("Exact value of b is : {0}", b);

    }

    ///////////////

    ///// 5. The following example demonstrates switch case statement in C#

    ///////////////

    public static void SwitchCaseStatement()

    {

         Console.WriteLine("-----------Switch case statement-----------");

         // Local variable

         char grade = 'B';

         switch (grade) {

            case 'A':

               Console.WriteLine("Excellent!");

               break;

            case 'B':

            case 'C':

               Console.WriteLine("Well done");

               break;

            case 'D':

               Console.WriteLine("You passed");

               break;

            case 'F':

               Console.WriteLine("Better try again");

               break;

               default:

            Console.WriteLine("Invalid grade");

               break;

         }

         Console.WriteLine("Your grade is  {0}", grade);

    }

    ///////////////

    ///// 6. The following example demonstrates nested switch case statement in C#

    ///////////////

    public static void NestedSwitchCaseStatement()

    {

         Console.WriteLine("-----------Nested switch case statement-----------");

         // Local variable

         int a = 100;

         int b = 200;

         switch (a) {

            case 100: 

            Console.WriteLine("This is part of outer switch ");

            switch (b) {

               case 200:

               Console.WriteLine("This is part of inner switch ");

               break;

            }

            break;

         }

         Console.WriteLine("Exact value of a is : {0}", a);

         Console.WriteLine("Exact value of b is : {0}", b);

    }

}