1903021101 闭腾 Java第十一周作业 Java的多态,继承

项目  内容
班级链接 19信计班(本)
作业链接 第十一周作业
博客名称 1903021101—闭腾—Java第十一周作业—Java的继承,多态
要求 每道题要有题目,代码(使用插入代码,不会插入代码的自己查资料解决,不要直接截图代码!!),截图(只截运行结果)。

 

 

  • *扩展阅读:Java中的继承和多态Java中的抽象类

  • 题目1:

    • 类Person定义了姓名name,出生年份birthYear,其子类Graduate在继承父类的基础上新增定义了成绩gpa、毕业年份graduateYear。编写测试类,输出毕业生的姓名、年龄、毕业年份、成绩。

    • 提示:父类要有构造方法,子类通过super调用父类构造方法。
    • 代码如下
    • package xjweek11;
      
      public abstract class Person {
            public String name;
            public double birthYear;
            public Person(String name, double birthYear) {
                  super();
                  this.name = name;
                  this.birthYear = birthYear;
              }
               public String getMessage() {
                   return "姓名:" +name;
               }
      
      }
      
      
      
      
      package xjweek11;
      
      public class Graduate extends Person {
          int gpa;
          int graduateYear;
          int nowYear;
      
          public Graduate(String name, double birthYear, int i, int j, int k) {
              super(name, birthYear);
              // TODO Auto-generated constructor stub
              this.nowYear = nowYear;
              this.gpa = gpa;
              this.graduateYear = graduateYear;
          }
          public String getMessage() {
              return super.getMessage()+"\n毕业年份:"+graduateYear+"\n成绩:"+gpa;
         }
         public double age() {
             double nowYear = 2022;
             return nowYear-birthYear;
      }
      
      }
      
      
      
      
      
      package xjweek11;
      
      public class Test1 {
      
          public static void main(String[] args) {
              // TODO Auto-generated method stub
              Graduate g = new Graduate("张三",2000,2023,99,2022);
              System.out.println("毕业生信息为:"+g.getMessage());
              System.out.println("年龄为:"+g.age());
          
          }
      
      }

       

    • 运行截图
    •  

       

      题目2:

      • 定义一个基本类Shape,有一个draw方法,定义三个类Circle(圆)、Triangle(三角形)、Square(正方形)都继承于Shape。在测试类中定义一个方法doStuff,传入基本类shape为参数,并调用draw方法。使用父类Shape创建三个类Circle、 Triangle、Square的实例对象并分别作为参数传入draw方法中。
      • 代码如下
      • package xjweek11;
        
        public abstract class Shape {
            
            void draw(){
                
            }
        
        }
        
        
        
        
        package xjweek11;
        
        public class Circle extends Shape {
            void draw(){
                System.out.println("Circle.draw()");
            }
        
        }
        
        
        
        
        
        
        package xjweek11;
        
        public class Triangle extends Shape {
            void draw(){
                System.out.println("Triangle.draw()");
            }
        
        }
        
        
        
        
        
        
        
        
        package xjweek11;
        
        public class Square extends Shape {
            void draw(){
                System.out.println("Spuare.darw()");
            }
        
        }
        
        
        
        
        
        
        
        
        
        
        
        
        package xjweek11;
        
        public class Test3 {
        
            
                // TODO Auto-generated method stub
                static void doStuff(Shape s){
                    s.draw();
                }
                public static void main(String[] args) {
                    Shape c=new Circle();
                    Shape s=new Square();
                    Shape t=new Triangle();
                    doStuff(c);
                    doStuff(s);
                    doStuff(t);
            }
        
        }

        运行截图:

      •  

         

    • 题目3:

      • 所有的动物都有一个父类Animal,再定义两个子类Bird(鸟)和Dog(狗)继承自Animal,并实现父类中的bark(叫唤)方法。

      • 提示:抽象
      • package xjweek11;
        
        public abstract class Animal {
             void bark(){
                 
             }
        
        }
        
        
        
        package xjweek11;
        
        public class BIrd extends Animal {
            void bark(){
                System.out.println("鸟是这样叫:呀呼!");
            }
        }
        
        
        
        package xjweek11;
        
        public class Dog extends Animal {
             void bark(){
                    System.out.println("狗是这样叫:嗨害嗨!");
                }
        
        }
        
        
        
        package xjweek11;
        
        public class Test {
        
            public static void main(String[] args) {
                // TODO Auto-generated method stub
                BIrd b = new BIrd();
                Dog d = new Dog();
                b.bark();
                d.bark();
        
            }
        
        }

        运行截图

      •  

         

      •  

        题目4:

        • 不同几何图形的面积计算公式是不一样的,可是,它们具有的特性是一样的,都具有长和宽这两个属性,也都具有面积计算的方法。根据抽象的概念计算长方形的面积和三角形的面积。

         

         代码如下:

      • package edu.xj.cxn.week11;
        
        public  abstract class Xingzhuang {
        int width;
        int height;
        public Xingzhuang(int width, int height) {
            super();
            this.width = width;
            this.height = height;
        }
        public  abstract double area();
        }
        
        
        **Trigon子类:**
        package edu.xj.cxn.week11;
        
        public class Trigon extends Xingzhuang {
        
            public Trigon(int width, int height) {
                super(width, height);
                // TODO Auto-generated constructor stub
            }
            public double area(){
                return (width*height)/2;
        }
        }
        
        **Rectangle子类:**
        package edu.xj.cxn.week11;
        
        public  class Rectangle extends Xingzhuang {
        
            public Rectangle(int width, int height) {
                super(width, height);
                // TODO Auto-generated constructor stub
            }
         public double area(){
            return width*height;
        }
        }
        
        
        **测试类:**
        package edu.xj.cxn.week11;
        
        public class Text4 {
        
            public static void main(String[] args) {
                Rectangle r=new Rectangle(6,5);
                System.out.println("长方形的面积为:"+r.area());
                Trigon t=new Trigon(4,6);
                System.out.println("三角形的面积为:"+t.area());
                // TODO Auto-generated method stub
        
            }
        
        }

         

        • 运行截图
        • 阅读心得:

          继承和多态是面向对象开发语言中非常重要的一个环节,若使用得当,整个程序的架构将变得非常有弹性,同时可以减少代码的冗余性。

posted @ 2022-05-15 23:18  DOUBLE尖  阅读(4)  评论(0编辑  收藏  举报