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
.
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Special C# Identifiers (Contextual Keywords) | |||||||||||||||
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Contextual Keywords (Used in Queries) | |||||||||||||||
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