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Terms
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What are Methods?
A method is a
set of code which is referred to by name and can be called (invoked) at
any point in a program simply by utilizing the method's name.
Think of a method as a subprogram that acts on data and often returns a
value.Each method has
its own name. When that name is encountered in a program, the execution
of the program branches to the body of that method. When the method is
finished, execution returns to the area of the program code from which
it was called, and the program continues on to the next line of code.
Good programmers write in a
modular fashion which allows for several programmers to work
independently on separate concepts which can be assembled at a later
date to create the entire project. The use of methods will be our
first step in the direction of modular programming.
Methods are time savers, in that they allow for the repetition of
sections of code without retyping the code. In addition, methods
can be saved and utilized again and again in newly developed programs.
You are using
methods when you use
System.out.print( ) and
System.out.println( ).
There are two
basic types of methods:
Built-in:
Build-in
methods are part of the compiler package, such as System.out.println( )
and System.exit(0).
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User-defined:
User-defined
methods are created by you, the programmer. These methods take-on
names that you assign to them and perform tasks that you create. |
How to invoke (call) a method (method
invocation):
When a method is
invoked (called), a request is made to perform some action, such as
setting a value, printing statements, returning an answer, etc.
The code to invoke the method contains the name of the method to be
executed and any needed data that the receiving method requires.
The required data for a method are specified in the method's parameter
list.
Consider this
method that we have already been using from Breezy;
int
number = Console.readInt("Enter a number"); //returns a value
The method name is "readInt"
which is defined in the class "Console".
Since the method is defined in the class
Console, the word
Console
becomes the calling object. This particular method returns an integer
value which is assigned to an integer variable named
number.
You invoke (call) a
method by writing down the calling object followed by a dot, then the name of
the method, and finally a set of parentheses that may (or may not) have
information for the method.
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