Substring/Top and tail: Difference between revisions

''See also [[#Delphi|Delphi]]''

{{works with|Extended Pascal}}

<lang pascal>program topAndTail(output);

var

line: string(20);

begin

line := 'ABCDEF';

if length(line) > 1 then

begin

{ string with first character removed }

writeLn(subStr(line, 2));

{ index range expression: only possible for strings }

{ _not_ designated `bindable` [e.g. `bindable string(20)`] }

writeLn(line[2..length(line)]);

{ string with last character removed }

writeLn(subStr(line, 1, length(line) - 1));

{ only legal with non-bindable strings: }

writeLn(line[1..length(line)-1])

end;

{ string with both the first and last characters removed }

if length(line) > 2 then

begin

writeLn(subStr(line, 2, length(line) - 2));

{ only for non-bindable strings: }

writeLn(line[2..length(line)-1])

end

end.</lang>It is imperative that <tt>firstCharacterIndex + substringLength</tt> specified to <tt>subStr(source, firstCharacterIndex, substringLength)</tt> must be valid index in <tt>source</tt>. Therefore you need to perform checks beforehand.