Editing Pascal (programming language) (section)

===Procedures and functions===
Pascal structures programs into procedures and functions. Generally, a procedure is used for its side effects, whereas a function is used for its return value.

:<syntaxhighlight lang="pascal">
program Printing(output);

var i : integer;

procedure PrintAnInteger(j : integer);
begin
    ...
end;

function triple(x: integer): integer;
begin
	triple := x * 3
end;

begin { main program }
    ...
    PrintAnInteger(i);
    PrintAnInteger(triple(i))
end.
</syntaxhighlight>

Procedures and functions can be nested to any depth, and the 'program' construct is the logical outermost block.

By default, parameters are passed by value.  If 'var' precedes a parameter's name, it is passed by reference.

Each procedure or function can have its own declarations of goto labels, constants, types, variables, and other procedures and functions, which must all be in that order.
This ordering requirement was originally intended to allow efficient [[single-pass compilation]]. However, in some dialects (such as [[Delphi (software)|Delphi]]) the strict ordering requirement of declaration sections has been relaxed.