Conditional statements

The if statement

The if-statement is a selection statement. It directs the control flow of your C# program. It is translated to intermediate language instructions called branches. It makes a logical decision based on a parameter or a user's input. Expressions in an if-statement evaluate always to true or false.

Example: Find the greater of two numbers using if statement?

class Program

    {

        public static void Main()

        {

            int a, b;

            Console.WriteLine("Enter two numbers: ");

            a = int.Parse(Console.ReadLine());

            b = int.Parse(Console.ReadLine());

            if (a > b)

            {

                Console.WriteLine("{0} is greater than {1}", a, b);

            }

            else if (a < b)

            {

                Console.WriteLine("{0} is greater than {1}", b, a);

            }

            else

            {

                Console.WriteLine("Both are equal");

            }

            Console.ReadLine();

        }      

    }

The switch statement

 

The switch statement selects for execution a statement list having an associated switch label that corresponds to the value of the switch expression.

switch-statement:

switch   (   expression   )   switch-block

switch-block:

{   switch-sections_opt   }

switch-sections:

switch-section
switch-sections   switch-section

switch-section:

switch-labels   statement-list

switch-labels:

switch-label
switch-labels   switch-label

switch-label:

case   constant-expression   :
default   :

A switch-statement consists of the keyword switch, followed by a parenthesized expression (called the switch expression), followed by a switch-block. The switch-block consists of zero or more switch-sections, enclosed in braces. Each switch-section consists of one or more switch-labels followed by a statement-list

 Example:

 

Console.WriteLine("Do you enjoy C# ? (yes/no/maybe)");

string input = Console.ReadLine();

switch(input.ToLower())

{

    case "yes":

    case "maybe":

        Console.WriteLine("Great!");

        break;

    case "no":

        Console.WriteLine("Too bad!");

        break;

    default:

        Console.WriteLine("I'm sorry, I don't understand that!");

        break;

}

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