Java程序设计4：类与对象

学习目标：

• 参数的传值
• 对象的组合

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学习内容：

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1. 掌握 对象的组合
2. 掌握参数的传递
3. 掌握关联关系和依赖关系UML图

学习记录

• 技术笔记 3个
• 优快云 技术博客 1 篇
• 学习的 vlog 视频 1 个

package com.prameter;//4-6
class Computer{
    int add(int x,int y) {
        return x+y;
    }
}
public class Example4_6 {
    public static void main(String[] args) {
        Computer com =new Computer();
        int m=100;
        int n=200;
        int result =com.add(m,n);
        System.out.println(result);
        result = com.add(200+m,n*10+8);
                                                                                                                                                                                                                                                                                                                                                                                                                               System.out.println(result);
    }
}

package com.batteryuse;
class Battery{
    int electricityAmout;
    Battery(int amount){
        electricityAmout=amount;
    }
}
class Radio{
    void openRadio(Battery battery){
        battery.electricityAmout= battery.electricityAmout-10;//消耗电量
    }
}
public class Example4_7 {
    public static void main(String[] args) {
        Battery nanfu =new Battery(100);
        System.out.println("南孚电池消耗电量"+nanfu.electricityAmout);
    }
}

package com.circular;

public class Example4_8 {
    public static void main(String[] args) {
        Circle circle = new Circle();//代码1
        circle.setRadius(10);//代码2
        Circular circular = new Circular();//代码3
        System.out.println("circle的引用："+circle);
        System.out.println("圆锥的bottom的引用："+circular.bottom);
        circular.setHight(5);
        circular.setBottom(circle);//代码4
        System.out.println("circlr的引用"+circle);
        System.out.println("圆锥的bottom的引用："+circular.bottom);
        System.out.println("圆锥的体积："+circular.getVolume());
        System.out.println("修改circular的半径，bottom的半径同样变化");
        circle.setRadius(20);//代码5
        System.out.println("bottom的半径："+circular.getBottomRadius());
        System.out.println("重新创建circle,circle的引用将发生变化");
        circle = new Circle();//代码6
        System.out.println("circle的引用："+circle);
        System.out.println("但是不影响circular的bottom引用");
        System.out.println("圆锥的bottom引用"+circular.bottom);
    }
}
 class Circle  {
    double   radius,area;
    void setRadius(double r){
        radius =r;
    }
    double getRadius(){
        return radius;
    }
    double getArea(){
        area = 3.14*radius*radius;
        return area;
    }
}
class Circular{
    Circle bottom;
    double height;
    void setBottom(Circle c){
        bottom = c;
    }
    void setHight(double h){
        height =h;
    }
    double getVolume(){
        if (bottom ==null)
            return -1;
        else
            return bottom.getArea()*height/3.0;
    }
    double getBottomRadius(){
        return bottom.getRadius();
    }
    public void setBottomRadius(double r){
        bottom.setRadius(r);
    }
}

E:\openjdk-14+36_windows-x64_bin\jdk-14\bin\java.exe "-javaagent:G:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2021.3.2\lib\idea_rt.jar=50803:G:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2021.3.2\bin" -Dfile.encoding=UTF-8 -classpath G:\Users\Administrator\IDEA_projects\java-01\out\production\java-09 com.circular.Example4_8
circle的引用：com.circular.Circle@7cc355be
圆锥的bottom的引用：null
circlr的引用com.circular.Circle@7cc355be
圆锥的bottom的引用：com.circular.Circle@7cc355be
圆锥的体积：523.3333333333334
修改circular的半径，bottom的半径同样变化
bottom的半径：20.0
重新创建circle,circle的引用将发生变化
circle的引用：com.circular.Circle@3d494fbf
但是不影响circular的bottom引用
圆锥的bottom引用com.circular.Circle@7cc355be

Process finished with exit code 0