6. Java Fundamentals-two-dimensional arrays and object-oriented understanding

1: Two-dimensional array (understanding)
(1) The element is an array of one-dimensional arrays.
(2) Format:
A: Data type [] Array name = new data type [m][n];
B: Data type [] Array name = new data type [m][];
C: Data type [] Array name = new data type [][]{{...},{...},{...}};
D: Data type [] Array name = {{...},{...},{}};
(3) Case (Master):
A: Traversal of two-dimensional arrays
B: Sum of two-dimensional arrays
C: Yang Hui Triangle

2: Two study questions (understanding)
(1) Problem of parameter Passing in Java
Only values are passed in Java.
　　　　 Basic Type：changes in formal parameters do not affect actual parameters
　　　　 Reference type：the change of formal parameters directly affects the actual parameters
(2) Data encryption issues
Synthesis of small cases.

3: Object-oriented (mastering)
(1) Object-oriented
Object-oriented is a process-oriented programming idea
(2) Object-oriented thought characteristics
A: It's a thought that's more in line with our thinking habits.
B: Simplifying Complex things
C: Let's turn from the executor to the conductor

Example: Buying a computer, washing clothes, cooking ... Everything is object.
(3)put the elephant in the refrigerator
A: Process-oriented implementation
B: Object-oriented implementation
Note: How do we make our operations more consistent with object-oriented thinking?
A: What are the classes
B: What are the members of each class
C: Class-To-class relationships
(4) Classes and objects
A: Things in the real world
Basic description of a property thing
The function of a behavioral thing
The most basic unit in the B:java language is the class. So, we're going to use classes to show things.
C: Class
member variables Things properties
Member Methods thing behavior
D: Class: Is a set of related properties and behaviors. is an abstract concept.
Object: is the concrete existence of this kind of thing, is a concrete instance. Object

Example: Student: Class
Monitor: Object
(5) Definition and use of class
A: Definition of class
The member variable definition format is the same as before, where the location is different, in the class, outside the method.
The member method definition format is the same as before, which is to remove the static.
B: Use the contents of the class
A: Create an object? Format
Class Name Object name =Newclass name ();
B: How do I use member variables and member methods?
Object name. Member Variable
The name of the object. Member method ()
(6) Case:
A: Definition and use of student class
B: Definition and use of mobile phone class
(7) Memory diagram
A: Memory diagram of an object
B: Memory diagram of two objects
C: Memory diagram of three objects
(8) Development, design, and characteristics of Java programs
A: Development: Is the constant creation of objects, through the object call function
B: Design: To manage and maintain relationships between objects
C: Features
A: Package
B: Inheritance
C: polymorphic

6. Java Fundamentals-two-dimensional arrays and object-oriented understanding