第9次作业--接口及接口回调

柱体类
/**创建一个柱体类Cone，定义柱体的高、构造方法、换底方法和求体积方法*/
 1 package package1;
 2 
 3 
 4 public class Cone  {
 5     Shape shape;
 6     double high;
 7     
 8     public Cone(Shape shape,double high){
 9         this.shape=shape;
10         this.high=high;
11     }
12     
13     public double getVolume(){
14         return shape.getArea()*high;
15     }
16     public void setShape(Shape shape){
17         this.shape=shape;
18     }
19 }

矩形类 
                   /** 创建一个矩形类Rectangle,继承shape接口，定义长和宽，定义构造方法和重写求面积方法*/

1 package package1;
 2 
 3 public class Rectangle implements Shape {
 4 protected double width;
 5 protected double length;
 6 public Rectangle(double width,double length){
 7     this.width=width;
 8     this.length=length;
 9 }
10  Rectangle() {
11     
12 }
13  public double getArea(){
14      System.out.println("r");
15      return width*length;
16  }
17      
18 }

正方形类
/*创建一个正方形类Zheng 继承接口Shape,定义边长、构造方法、求面积方法*/
 1 package package1;
 2 
 3 public class Zheng implements Shape{
 4     double side;
 5     public Zheng(double side) {
 6         this.side =side;
 7     }
 8  public double getArea(){
 9      return side*side;
10  }
11 }

三角形类

/*创建一个三角形类Triangle继承shape接口，定义三边a，b，c，定义构造方法、求面积方法*/

 1 package package1;
 2 
 3 public class Triangle implements Shape {
 4 double a;
 5 double b;
 6 double c;
 7 
 8 public Triangle(double a,double b,double c){
 9     this.a=a;
10     this.b=b;
11     this.c=c;
12 }
13 public double getArea() {
14     System.out.println("t");
15     double p =(a+b+c)/2;
16     return Math.sqrt(p*(p-a)*(p-b)*(p-c));
17     
18 }
19 }

 梯形类
/*创建一个梯型类，继承Shape接口，定义上底、下底和高、定义构造方法、定义求面积方法*/
1 package package1;
 2 
 3 public class Tixing implements Shape{
 4     double a;
 5     double b;
 6     double high;
 7     Tixing(double a,double b,double high){
 8         this.a=a;
 9         this.b=b;
10         this.high=high;
11     }
12 
13     public double getArea(){
14         return (a+b)*high/2;
15     }
16 }

圆形类
/*创建一个圆形类Circ继承接口Shape,定义半径r，常量PI，定义构造方法和求面积方法*/
 1 package package1;
 2 
 3 public class Circ implements Shape{
 4     double r;
 5     final double PI=3.14;
 6     public Circ(double r) {
 7         this.r=r;
 8     }
 9     public double getArea() {
10         return r*r*PI;
11         
12     }
13 
14 }

工厂类
/*创建一个工厂类Factory，声明Shape对象为空，引用输入操作提示用户输入字符，利用switch语句给柱体赋底,数据回调给接口Shape*/
 1 package package1;
 2 
 3 import java.util.Scanner;
 4 
 5 public class Factory {
 6 
 7     Shape shape = null;
 8     Scanner reader = new Scanner(System.in);
 9     
10     public Shape getShape(){
11         char i =reader.next().charAt(0);
12         switch (i) {
13         case 'j':System.out.println("以矩形为底的柱体体积是：");shape=new Rectangle(2, 3); break;
14         case 'z':System.out.println("以正方形为底的柱体体积是：");shape=new Zheng(4); break;
15         case 's':System.out.println("以三角形为底的柱体体积是：");shape=new Triangle(2, 3, 4);  break;
16         case 't':System.out.println("以梯形为底的柱体体积是：");shape=new Tixing(2, 3, 4); break;
17         case 'y':System.out.println("以圆形为底的柱体体积是：");shape=new Circ(5); break;
18         }
19         return shape;
20     }
21 }

接口

/*定义接口Shape,抽象方法getArea*/

1 package package1;
2 
3 public interface Shape {
4    abstract double getArea();
5 }

主类

/*定义变量high作为主体的高，通过Scanner方法输入高。用for循环输出五个图形为底的体积，创建一个工厂类对象，一个柱体类对象，引用换底方法，输出柱体的体积*/
1 package package1;
 2 import java.util.Scanner;
 3 
 4 public class Test {
 5 
 6     
 7     public static void main(String[] args) {
 8         System.out.println("请输入柱体的高：");
 9         double high;
10         Scanner reader =new Scanner(System.in);
11         high=reader.nextDouble();
12         for(int i=0;i<5;i++){
13              System.out.println("请选择柱体的底面图形，j为矩形、z为正方形、s为三角形、t为梯形、y为圆形");
14             Factory factory = new Factory();
15             Cone cone = new Cone(factory.getShape(), high);
16             cone.setShape(factory.shape);
17             System.out.println(cone.getVolume());
18         }    
19     }
20 }

运行结果