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  • JAVA语言程序设计课后习题----第七单元解析(仅供参考)

    1  本题水题,就是想让你理解继承的含义

    1 public class Animaal {
    2     public double weight;
    3     public void eat(){
    4     }
    5 }
    1 public class Bird extends Animaal {
    2     public int numberOfFins;
    3     public void fly(){}
    4 
    5 
    6 }
    1 public class Dog extends Animaal {
    2     public int numberOflegs;
    3     public void walk(){}
    4 
    5 
    6 }
    1 public class Fish extends Animaal{
    2     public int numberOfFins;
    3     public void swim(){}
    4 
    5 
    6 }

     2  本题主要考类的继承和方法的重写,方法的重写关键字@Override

    1 public class Circle {
    2     public int radius;
    3     public double getArea(){
    4         return Math.PI*radius*radius;
    5     }
    6 }
     1 public class Cylinder extends Circle {
     2     public double height;
     3 
     4     public Cylinder() {
     5     }
     6 
     7     public Cylinder(double height) {
     8         this.height = height;
     9     }
    10     public Cylinder(int radius,double height){
    11         this.radius=radius;
    12         this.height=height;
    13     }
    14     //    体积
    15     public double getVolume(){
    16         return Math.PI*radius*radius*height;
    17     }
    18     //    覆盖Circle 里面的getArea函数求圆柱的体积
    19     @Override
    20     public double getArea(){
    21         return Math.PI*radius*radius*2+2*Math.PI*radius*height;
    22     }
    23 }
     1 import java.util.Scanner;
     2 
     3 public class ch08 {
     4     public static void main(String[] args) {
     5 
     6         Scanner input = new Scanner(System.in);
     7         System.out.println("请输入圆柱的半径、高");
     8         Cylinder cylinder = new Cylinder(input.nextInt(),input.nextDouble());
     9         System.out.println("圆柱的体积为:"+cylinder.getVolume());
    10         System.out.println("圆柱的面积为:"+cylinder.getArea());
    11     }
    12 }

     3  本题水题,考的方法和上面两题类似,注意题目要求即可

     1 public class Auto {
     2     public double speed;
     3     //    启动的方法
     4     public void start(){
     5         System.out.println("插上钥匙、系上安全带、一脚把离合踩到底、挂上一档、打左转向、缓慢抬脚、汽车平稳启动");
     6     }
     7     //    加速的方法
     8     public void speedUp(){
     9         System.out.println("脚慢踩油门、松开油门、踩离合到底、换挡、加速完成");
    10     }
    11     //    停止的方法
    12     public void stop(){
    13         System.out.println("慢踩刹车、达到额定速度、松开刹车、踩离合、换挡、持续到速度为0");
    14     }
    15 }
    1 public class Bus extends Auto {
    2     public int passenger;
    3     public Bus(int passenger){this.passenger=passenger;}
    4     //    上车
    5     public int gotOn(){ return ++passenger;
    6     }
    7     //    下车
    8     public int gotOff(){return --passenger;}
    9 }
     1 import java.util.Scanner;
     2 
     3 public class ch09 {
     4     public static void main(String[] args) {
     5         Scanner input = new Scanner(System.in);
     6         System.out.println("请输入开始车上的人数");
     7         Bus bus = new Bus(input.nextInt());
     8         System.out.println("旅客上车");
     9         System.out.println(bus.gotOn());
    10         bus.start();
    11         bus.speedUp();
    12         System.out.println("旅客上下车");
    13         System.out.println(bus.gotOff());
    14         bus.stop();
    15     }
    16 }

    4  本题主要考继承和抽象方法,关键字@Override

     

    1 public class Shape {
    2     public int radius;
    3     public int l;
    4     public double getPrimeter(){
    5         return 0;
    6     }
    7     public double getArea(){return 0;}
    8 }
     1 public class Square extends Shape {
     2     public Square() {
     3     }
     4 
     5     public Square(int radius){this.radius=radius;}
     6     @Override
     7     public double getPrimeter(){
     8         return 4*radius;
     9     }
    10     @Override
    11     public double getArea(){
    12         return radius*radius;
    13     }
    14 
    15 }
    1 public class ch10 {
    2     public static void main(String[] args) {
    3         Square square = new Square(10);
    4         System.out.println("正方形的周长为:"+square.getPrimeter());
    5         System.out.println("正方形的面积为:"+square.getArea());
    6     }
    7 }

    5  本题主要考方法的覆盖,构造方法的重写

    1 public class Rectangle {
    2     public double length,width;
    3 
    4     public Rectangle(double length, double width) {
    5         this.length=length;
    6         this.width=width;
    7     }
    8 }
     1 public class Cuboid extends Rectangle{
     2     public double height;
     3 
     4     public Cuboid(double length, double width, double height) {
     5         super(length, width);
     6         this.height = height;
     7     }
     8 
     9     public double volume(){
    10         return length*width*height;
    11     }
    12 }
    1 public class ch11 {
    2     public static void main(String[] args) {
    3         System.out.println("长方体的长、宽、高分别为10、5、2!");
    4         Cuboid cuboid = new Cuboid(10,5,2);
    5         System.out.println("长方体的体积为:"+cuboid.volume());
    6     }
    7 }
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  • 原文地址:https://www.cnblogs.com/PerZhu/p/10892240.html
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