Procedures

    Pascal allows you to create procedures. A procedure is a type of
    subprogram and has a syntax nearly identical to that of programs, with
    one major exception: A procedure starts with a PROCEDURE header, which
    takes the form:

         procedure <name><parameters>;

    where <name> is any legal identifier not previously declared, and
    <parameters> is an optional list of parameters, enclosed in
    parentheses and separated by semicolons. (The other difference between
    a program and a procedure is that the main body of a procedure ends
    with a semicolon instead of a period.)

    A procedure is executed by referencing its name, including any
    necessary parameters. For example, if you declare this procedure:

         procedure Swap(var A,B : Integer);

         var
           T    : Integer;

         begin
           T := A;
           A := B;
           B := T
         end;

    then you can call it in your program like this (assuming I and J are
    integer variables):

         Swap(I,J);