Functions and Recursive Functions - A Concise and Practical Introduction to Programming Algorithms in Java - page 58

3.2 Declaring and calling functions

3.2.1 Prototyping functions

Functions should always be declared inside the body of a class: The program
class (for now). The generic syntax for declaring a function F that takes N
arguments arg1 , ..., argN of respective types Type1 , ..., TypeN and return a
result of type TypeR is:

static TypeR F(Type1 arg1, Type2 arg2, ..., TypeN argN)
{
TypeR result;
block_of_instructions;
return result;
}

Procedures are special functions that do not return any result. In Java, this
is specified by using the void keyword for the function return type. Thus the
declaration of a procedure is as follows:

static void Proc(Type1 arg1, Type2 arg2, ..., TypeM argM)
{
block_of_instructions;
return;
}

The last instruction statement return; in the procedure Proc may be omitted.
We always put the keyword static in front of procedure/function declarations:
static void Proc . We will explain why this is necessary in Chapter 5 dealing
with objects and methods. Since procedures and functions shall be attached to
the body of class (that is, encapsulated into the class), we have basically the
following program skeleton:

Program 3.1 Basic program skeleton for defining static functions
class ProgramSkeleton {

static TypeF F(Type1 arg1 , . . . , TypeN argN )

TypeF r e s u l t ;
// Description
Block − of − instructions ;
return result ;
}

static void Proc (Type1 arg1 , Type2 arg2 , . . . , TypeM argM)

{ block instructions ;
return ;
}