C# Programming/Keywords/if

The if keyword identifies an if statement with the following syntax:

if-statement ::= "if" "(" condition ")" if-body ["else" else-body]

condition ::= boolean-expression

if-body ::= statement-or-statement-block

else-body ::= statement-or-statement-block

If the condition evaluates to true, the if-body executes. Curly braces ("{" and " }") allow the if-body to contain more than one statement. Optionally, an else clause can immediately follow the if-body, providing code to execute when the condition is false. Making the else-body another if statement creates the common cascade of if, else if, else if, else if, else statements:

using System;

public class IfStatementSample
{
    public void IfMyNumberIs()
    {
        int myNumber = 5;
        if (myNumber == 4)
            Console.WriteLine("This will not be shown because myNumber is not 4.");
        else if(myNumber < 0)
        {
            Console.WriteLine("This will not be shown because myNumber is not negative.");
        }
        else if(myNumber%2 == 0)
            Console.WriteLine("This will not be shown because myNumber is not even.");
        else
        {
            Console.WriteLine("myNumber does not match the coded conditions, so this sentence will be shown!");
        }
    }
}

The boolean expression used in an if statement typically contains one or more of the following operators:

See also else.