Java train - Classes and Objects chapter

First, object-oriented

Teacher's Day approaching, a group of students summoned a blackboard, how to complete it? For a child, you tell him: "We want to determine the blackboard theme, clearly the gist of content, search specific content, layout ideas, drawing and writing, arrange logistical assistance." He might froze in place, I do not know the it measures. But you just have to give every child said, "You want to make water, wash rag, when Xiao Ming a mistake, he put a wet rag to clean the blackboard." ....... When we determine to be a blackboard schoolchildren What people, everyone just needs to do what, and with whom, to whom do the blackboard will be able to complete this matter.

Java is an object-oriented programming language: the problem transaction into individual objects, each object has to determine how state and behavior in problem-solving process, build relationships, solve common or description of the transaction. In short, create an object, describe the state and behavior, resolve or describe things through mutual relations.

Object: a specific entity, a specific thing.

 Second, the class

Class: an Object "class" have the same characteristics and behavior.

The role of class: as a template with a particular feature or behavior, the use of bulk.

Method → ​​→ behavior characteristic properties

Class is created:

      Keywords: class

      Format: public class name of the class {}

Class property definitions:

       Format: public property type name;

The method of the class definition:

       Format: public method return type method name (parameter type parameter name, ......) {

                                                  The method body

                                              }

(Common types: int Integer, String string)

note:

1.  is public access can be modified.
2. Between different parameters, separated.
3. The method requires the use of external conditions: method parameters. It may be an object.
4. When the method does not return a value, with void. void is a command, the method returns no value.
5. The method requires the use of their property, write directly attribute name; other classes of property xx, xx property name (xx for the other classes in the class name).

Three, Java objects in

Objects created:

        Keywords: new

        Format: class name = new class name object name ();

Use properties of the object:

        Format: Object Name property name;

The method of using an object:

        Format: Method name object name (parameter value, ......);