java object-oriented practice 1

/*

• java object-oriented
• Three main lines
• 1, members of the class and the class java
• Members of the class: properties, methods, constructors, code blocks, inner class
• 2, three characteristics of object-oriented
• Encapsulation (Encapsulation), polymorphism (Polymorphism), inherited (Inheritance), (abstract abstractness)
• 3. Use other keywords
• this，super，static，final，abstract，interface，package，import
• Etc.
  * /

/*

• Object Oriented (OOP Object Oriented Programming) and the process-oriented (POP Procedure Oriented Programming) Comparative
• 1, both a thought, is relative to the object-oriented process-oriented, process-oriented, emphasizing the functional behavior in order to function as the smallest unit, consider how to do it.
• Object-oriented, functional encapsulated into objects, have emphasized the object function to the class / object as a minimum unit, considered by whom.
• 2, more emphasis on the use of object-oriented logical thinking human thinking routine methods and principles used, e.g. abstract, classification, inheritance, polymerization, polymorphic
• For example child: to achieve "who put the fruit into the refrigerator."
• A process-oriented:
• 1, open the refrigerator door
• 2, pick up fruit in the refrigerator
• 3, close the refrigerator door
• Second, the object-oriented
• 1, target: human - Step 1: Open (Object 1: refrigerator) door: Step 2: Pick up (Object 2: fruits), Step 3: Close (Object 1: refrigerator) door
• 2, the object 1: Refrigerator - Function 1: to open, function 2: Block
• 3, the object 2: Fruit - Function 1: can be picked up
• After instantiating the object, call the appropriate function related objects designed to achieve.
• Object-oriented design
• A programmer by the executor of process-oriented object-oriented commander turned
• Second, the object-oriented analysis of the problem steps:
• 1, according to the issues to choose real-world entities for the issue.
• 2, from the entity seeking to solve problems related to the properties and functions of these attributes and functions evolved into the concept of world class
• 3, the abstract entities described in a computer language, the computer world is formed in the definition of classes, i.e., by some kind of programming language,
• The computer can be configured to identify the type and structure of data processing
• 4, the class instance into the computer world object, the object is the ultimate tool for computer-world problem-solving
• example
• The amount of the ticket conductor statistics
• Conductor and tickets can be a class
• Statistical method conductor of the action is, where the ticket is the amount of data
• General terms can create classes, methods verb class
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/*

• Object-oriented two elements:
• Class (class) and the object (Object) is the core object-oriented concepts, all things are all objects
• Class 1 is a description of a class of things, is to define the abstract concept
• 2 is an individual objects such things actually exist, which is also known instances (Instance).
• Abstract = class people, a specific individual target =
• Object-oriented programming focused on the design of the class
• The design is the design class class members, depending on the object that has the function of class design

*/

/*

• World java code from a variety of different functions of classes
• Class members in common:
• 1, Properties Field (translated domain or field) = class member variable corresponding to
• 2, the behavior of the method (function) corresponding to the class membership = Method (function)
• Object class = class is created to instantiate instances of classes =
• Corresponds to the real world, human beings have attributes such as age, height, there is talk of running and other functions
• Syntax class
• Modifiers class class name {// consider modifier (if needed), the class name (whether the same name, whether a keyword, whether clear image)
• Property declaration; // (modifiers, property type, property name, initial value)
• The method of statement; // (modifier, return type, method name, parameters, etc.)
• }
• Description: modifier can be expressed in any public access
• Private modifier representation can be accessed only within the class
• {} Class required body wrap
• example
• public class Person1{
• private int age; // declare a private variable age
• public void showAge (int i) {// declare a method showAge ()

•  age = i;
  

• }
• }

*/

/*

• The use of classes and objects (object-oriented implementation)
• 1, create a class, members of the design class
• 2, create a class of objects
• 3, by calling the object "Object Property" or "object. Method" related functions
• Note: If more than one object of a class created, each object has its own set of classes of property (non-static case)
• In a separate memory space, the initialization value of the property with a value of initializing the same dimensional array
• If you modify the properties of an object does not affect another property of the object
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/*

• Create and use objects: Memory resolved
• A stack (Heap), the sole purpose of this memory area is stored object instance, almost all of the object instances to allocate memory here,
• Described in the java virtual machine is: all object instances and arrays should be allocated on the heap
• 2, typically of said stack (Stack), the stack is a virtual machine, a virtual machine for storing a stack of local variables, local variable table storage
• Compiler known various basic data types (boolean, byte, char, short, long, float, double) the length,
• Object reference (reference type, it is not identical with the object itself, but the first target address in the heap memory). After the implementation of the method, automatic release
• 3, method area (Method Area), class information for storing the virtual machine has been loaded, a constant, static variables, the real-time data such as the code compiler

*/

package com.atguigu.contact;

public class Object1 {
	public static void main(String[] args) {//测试类中创建main方法作为入口
		Person people = new Person();//实例化Person类
		//调用属性格式 ：对象.属性
		people.name = "john";
		people.age = 18;
		people.isMarried = false;
		people.gender = '男';//调用属性赋值
		//调用方法格式 ：对象.方法
		people.eat();
		people.talk();
		people.sleep();
		people.work();
		System.out.println(people.display(1));//调用方法输出
		Person1 people1 = new Person1();
		//调用构造器格式 ：对象.构造器(参数)
		people1.Person("Tom",30, false);//调用构造器赋值
		System.out.println(people1.display(2));//赋值后调用方法输出
	    //新创建一个对象，看属性的初始化值
		Person people2 = new Person();//方法内，局部变量
		System.out.println(people2.name);//null
		System.out.println(people2.age);//0
		System.out.println(people2.gender);//空值
		System.out.println(people2.isMarried);//false
		//
		Person people3 = new Person();
		people3 = people;
		people3.age = 10;
		System.out.println(people3.name);//输出john
		System.out.println(people.age);//输出10，与数组类似，直接赋值与复制不同
		//相当于将people 的地址赋值给people3，指向的是同一个内存空间。

				
}
}

class Person{
	String name;
	int age;
	char gender;
	boolean isMarried;//属性声明部分，成员变量
	public void eat() {//没有返回值需加 void
		System.out.println(name + "吃了一顿饭");
	}
	public void talk() {
		System.out.println(name + "唠了一会嗑");
	}
	public void sleep() {
		System.out.println(name + "睡了一会觉");
	}
	public void work() {
		System.out.println(name + "干了一会活");
	}
	public String display(int index) {//可以在括号里定义变量，在调用时赋值使用，形参，局部变量		
		return (index + "号人物名字是：" + name + "  年龄是：" + age + "  性别是：" + gender + "  是否已婚：" + isMarried);
	}//方法声明部分
}

class Person1{
	//属性
	String name;
	boolean isMarried;
	int age;
	//构造器
	public void Person() {}
	public void Person(String n,int num,boolean mark) {//形参，局部变量
		name = n;
		isMarried = mark;
		age = num;//构造器内部变量，局部变量
	
	}
	//方法
	public void walk () {
		System.out.println(name + "向前走了一段路");
	}
	public String display(int index) {
		return index + "号人物名字是：" + name  + "  年龄是：" + age + "  是否结婚" + isMarried;
	}
	//代码块
	{
		name = "hank";
		isMarried = true;
		age = 20;//代码块内，局部变量
	}
	//内部类
	class pet{
		String name;
		float weight;
	} 	
}