5 & test report summary seventh week course

Experiments four types of inheritance

• Purpose
• We understood that use of abstract classes and interfaces;
• Understand the role of the package, grasp the design of the package.
• Experimental requirements
• Master the method of abstract class.
• Mastery of technology and the use of system interfaces to create a custom interface methods.
• Understand the structure of the Java system package.
• Able to create a custom package method.
• Content Experiments
• (A) using the abstract class
• 1. Design of a class hierarchy, defines an abstract class - shape in which the abstract method including the area of the required shape. Inherit the abstract class defines triangle, rectangle, circle. Create a separate triangular, rectangular, round objects exist, the area of the output of various types of pattern.
     NOTE: triangle area s = sqrt (p * (pa ) * (pb) * (pc)) wherein, a, b, c of three sides, p = (a + b + c) / 2

  2. programming skills

  (1) abstract class defines a method to achieve specific class;

  (2) using the abstract class reference variable subclass can refer to objects;

  (3) subclass object reference by the parent class, by which the actual reference using the method is a method to access the object subclass. All objects may be deposited into the parent class definition array.

• package java实验报告五;
  
  public class Test1 {
  
      public static void main(String[] args) {
          Circle cir=new Circle(1);
          Triangle tr=new Triangle(1,1,1);
          Rectangle re=new Rectangle(1,1);
          cir.getArea();
          tr.getArea();
          re.getArea();
      }
  
  }

• package java实验报告五;
  
  public class Circle extends Shape {
      private double radius;
  
      public double getRadius() {
          return radius;
      }
  
      public void setRadius(double radius) {
          this.radius = radius;
      }
      
      public Circle(double radius){         
      }
      
      public double getArea(){              
          double Area=Math.PI*getRadius()*getRadius();
          System.out.println("圆的面积："+Area);
          return Area;
      }
      
  
  }

   

  package java实验报告五;
  
  public class Rectangle extends Shape {
  
      private double height;
      private double width;
      public double getHeight() {
          return height;
      }
      public void setHeight(double height) {
          this.height = height;
      }
      public double getWidth() {
          return width;
      }
      public void setWidth(double width) {
          this.width = width;
      }
      public Rectangle(double height,double width){
          this.height=height;
          this.width=width;
      }
      public double getArea() {
          double Area=getHeight()*getWidth();
          System.out.println ( "rectangular area:" Area +); 
          return Area; 
      } 
  
  }

• package java实验报告五;
  
  public class Triangle extends Shape {
      private double a,b,c,p;
      public double getA() {
          return a;
      }
  
      public void setA(double a) {
          this.a = a;
      }
  
      public double getB() {
          return b;
      }
  
      public void setB(double b) {
          this.b = b;
      }
  
      public double getC() {
          return c;
      }
  
      public void setC(double c) {
          this.c = c;
      }
  
      public double getP() {
          return p;
      }
  
      public void setP(double p) {
          this.p = p;
      }
      
      public Triangle(double a,double b,double c){
          this.a=a;
          this.b=b;
          this.c=c;
      }
      public double getArea() {
          p=(getA()+getB()+getC())/2;
          double Area=Math.sqrt((p*(p-getA())*(p-getB())*(p-getC())));
          System.out.println("三角形的面积："+Area);
          return Area;
      }
  
  }

   

  package java实验报告五;
  
  public class Test1 {
  
      public static void main(String[] args) {
          Circle cir=new Circle(1);
          Triangle tr=new Triangle(1,1,1);
          Rectangle re=new Rectangle(1,1);
          cir.getArea();
          tr.getArea();
          re.getArea();
      }

• 

   

   

  (B) interface technology used

  1 Interface Shape definitions, wherein the method comprises a size (), Design "straight line", "circle", Shape class implements the interface. Respectively, to create a "straight line", "circle" object, the size of various types of graphical output.

  2. Programming skills

  Method (1) defined in the interface to be rewritten to achieve specific implementation of the interface class;

  (2) using the interface type variables can be referenced object class is created that implements the interface.

• five experimental report package java demo2; 
  
  public interface the Shape { 
      public void size (); 
  
  }

• five experimental report package java demo2; 
  
  class the implements the Shape Line { 
      public void size () { 
          System.out.println ( "generates a straight line"); 
      } 
  
  }

• five experimental report package java demo2; 
  
  public class Circle the implements the Shape { 
      public void size () { 
          System.out.println ( "generates a circle"); 
      } 
  
  }

• package java实验报告五demo2;
  
  public class Test1 {
  
      public static void main(String[] args) {
          Line l=new Line( );
          l.size();
          Circle c=new Circle();
          c.size();
      
      }
  

   

   

   

•  Summary: This week study abstract classes, interfaces, abstract classes, interfaces instantiated template design abstract class, standard interfaces. Learn a bit difficult, I irritated