Extract file extension: Difference between revisions

=={{header|FreePascal}}==

<syntaxhighlight lang="pascal">Program Extract_file_extension;

{FreePascal has the built-in function ExtractFileExt which returns the file extension.

* it does need charachters before the period to return the proper extension and it returns

* the extension including the period}

Uses character,sysutils;

Const arr : array of string = ('http://example.com/download.tar.gz','CharacterModel.3DS','.desktop',

'document','document.txt_backup','/etc/pam.d/login');

Function extractextension(fn: String): string;

Var

i: integer;

Begin

fn := 'prefix' + fn; {add charachters before the period}

fn := ExtractFileExt(fn);

For i := 2 to length(fn) Do {skip the period}

If Not IsLetterOrDigit(fn[i]) Then exit('');

extractextension := fn;

End;

Var i : string;

Begin

For i In arr Do

writeln(i:35,' -> ',extractextension(i))

End.

</syntaxhighlight>

{{out}}

<pre>

http://example.com/download.tar.gz -> gz

CharacterModel.3DS -> 3DS

.desktop -> desktop

document ->

document.txt_backup ->

/etc/pam.d/login ->

</pre>