Function

A function is a declaration of a routine which may be invoked from within the unit that declares it, from outside the unit if the function is public, or from within a program, and the routine returns a value as part of its definition. A routine that does not return a value as part of its definition is a procedure, however, technically a function is also a procedure as well.

A function which is part of an object is called a property if it can be assigned a value, and a method if it cannot be assigned a value.

Addition of two integers example:

 function add(c1, c2 : integer) : integer;
 begin
 add := c1 + c2;
 end;

 var 
   result : integer;

 begin
   result := add(4, 5);
   writeln (result); // result is 9
 end.