Java语法基础练习题3

课堂练习4：

编写代码模拟手机与SIM卡的组合关系。

要求：

           SIM卡类负责创建SIM卡；

           Phone类负责创建手机；

          手机可以组合一个SIM卡；

          手机可以更换其中的SIM卡。

package test.sim;

import java.util.Scanner;

public class TestPhone {
public static void main(String[] args) {
Phone phone=new Phone("OPPO");
Sim sim=new Sim("18375433859");
System.out.println("默认手机是"+phone.GetPhone()+"\nSIM卡是"+sim.GetSim());

System.out.println("请输入手机型号：");
Scanner reader=new Scanner(System.in);
String p=reader.next();
phone.setPhone(p);
System.out.println("请输入手机SIM卡号：");
String s=reader.next();
sim.SetSim(s);
System.out.println("新手机是"+phone.GetPhone()+"\nSIM卡是"+sim.GetSim());
}

}

package test.sim;

public class Phone {

String p;
Phone(String p) {
this.p=p;
}
void setPhone(String p) {
this.p=p;
}
String GetPhone(){
return p;
}

}

package test.sim;

public class Sim {
String s;
Sim(String s) {
this.s=s;
}
void SetSim(String s){
this.s=s;
}

String GetSim(){
return s;
}

}



课堂练习5：



package test.cpu;

public class Test {
public static void main(String[] args) {
CPU cpu = new CPU();
cpu.setSpeed(200);
HardDisk disk = new HardDisk();
disk.setAmount(200);
PC pc =new PC();
pc.SetCpu(cpu);
pc.SetHardDisk(disk);
pc.show();

}

}

package test.cpu;

public class PC {
CPU cpu;
HardDisk HD;
void SetCpu(CPU c){
cpu = c;
}
void SetHardDisk(HardDisk h){
HD = h;
}
void show(){
System.out.print("CPU的速度是"+cpu.speed+"\n硬盘的容量是:"+HD.amount);
}

}

package test.cpu;

public class HardDisk {
int amount;
void setAmount(int m){
amount = m;
}
int getAmount(){
return amount;
}

}

package test.cpu;

public class CPU {
int speed;
void setSpeed(int m){
speed = m;
}
int getSpeed(){
return speed;
}

}



课堂练习6：

– 定义一个圆类(Circle)，其所在的包为bzu.info.software；定义一个圆柱类Cylinder，其所在的包为bzu.info.com；定义一个主类A，其所在的包也为bzu.info.com，在A中生成一个Cylinder对象，并输出其体积。编译并运行该类。

– 试着改变求体积方法的访问权限，查看并分析编译和运行结果

– 把Cylinder类和A类置于不同的包中，通过对求体积方法设置不同的访问权限，查看并分析编译和运行结果

package bzu.info.com;

import bzu.info.software.Circle;

public class A {

public static void main(String[] args) {
Circle circle = new Circle(10);
System.out.println("圆的半径"+circle.radius);     //输出圆circle的半径

Cylinder circular = new Cylinder(circle, 20);
System.out.println("圆锥的底圆半径:"+circular.getBottomRadius());    //输出圆锥的底圆半径
System.out.println("圆锥的体积:"+circular.getVolume());    //输出圆锥的体积
}

}
package bzu.info.com;

import bzu.info.software.Circle;

public class Cylinder {
public Circle bottom;
public double height;

public Cylinder(Circle c, double h){
bottom = c;
height = h;
}

double getBottomRadius(){
return bottom.radius;
}

void setBottomRadius(double r){
bottom.radius = r;
}

double getVolume(){
return bottom.getArea()*height/3.0;
}

}

package bzu.info.software;

public class Circle {
public double radius;
public Circle(double r){
radius = r;
}
public double getArea(){
return 3.14*radius*radius;
}

}