C# Programming/Keywords/if

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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:

Operator Meaning Operator Meaning
< less than > greater than
== equal to  != not equal to
<= less than or equal to >= greater than or equal to
&& and || or
 ! not

See also else.



C# Keywords
abstract as base bool break
byte case catch char checked
class const continue decimal default
delegate do double else enum
event explicit extern false finally
fixed float for foreach
goto if implicit in int
interface internal is lock long
namespace new null object operator
out override params private protected
public readonly ref return sbyte
sealed short sizeof stackalloc
static string struct switch this
throw true try typeof uint
ulong unchecked unsafe ushort using
var virtual void volatile while
Special C# Identifiers
add alias get global partial
remove set value where yield