Java上机实验4

1.设计一个抽象类图形类，在该类中包含有至少两个抽象方法求周长和求面积，分别定义圆形类、长方形类、矩形类来继承图形类，并实现上述两个方法。并创建实例验证。

2.package com.majing;3.4.public class test {5.public static void main(String[] args) {6.Roundness r = new Roundness(3);7.System.out.println(r.perimeter());8.System.out.println(r.area());9.10.Rectangle rec = new Rectangle(5,6);11.System.out.println(rec.perimeter());12.System.out.println(rec.area());13.14.Matrix m = new Matrix(12);15.System.out.println(m.perimeter());16.System.out.println(m.area());17.}18.19.}20.21.abstract class Graph {22.abstract double perimeter();23.abstract double area();24.}25.26.class Roundness extends Graph27.{28.private int radius;29.30.Roundness(int r)31.{32.radius = r;33.}34.35.double perimeter()36.{37.return 2*3.1415*radius;38.}39.40.double area()41.{42.return 3.14159*3.14159*radius;43.}44.}45.46.class Rectangle extends Graph47.{48.private double length;49.private double width;50.51.Rectangle(double l, double w)52.{53.length = l;54.width = w;55.}56.57.double perimeter()58.{59.return 2*(length + width);60.}61.62.double area()63.{64.return length*width;65.}66.}67.68.class Matrix extends Graph69.{70.private double side;71.72.Matrix(double s)73.{74.side = s;75.}76.double perimeter()77.{78.return 4*side;79.}80.81.double area()82.{83.return side*side;84.}85.}

2.创建以下几个接口：进食的接口、睡觉的接口、思考的接口、说话的接口。分别定义猫类、人类、鸟类来选择实现上述的接口，并创建实例验证。

package com.majing;public class test2 {public static void main(String[] args) {Cat c = new Cat();c.eat_things();c.say_ways();c.sleep_ways();Human h = new Human();h.eat_things();h.say_ways();h.sleep_ways();h.think_things();Birds b = new Birds();b.eat_things();b.sleep_ways();b.say_ways();}}interface Eat{void eat_things();}interface Sleep{void sleep_ways();}interface Think{void think_things();}interface Say{void say_ways();}class Cat implements Eat,Sleep,Say{public void eat_things(){System.out.println("Cat eat fish");}public void sleep_ways(){System.out.println("Cats sleep at cattery");}public void say_ways(){System.out.println("cats say miao miao");}}class Human implements Eat,Sleep,Think,Say{public void eat_things(){System.out.println("Human eat food and fruits");}public void sleep_ways(){System.out.println("Human sleep in their beds");}public void think_things(){System.out.println("Cars, house, mate");}public void say_ways(){System.out.println("They use their languages");}}class Birds implements Eat,Sleep,Say{public void eat_things(){System.out.println("Birds eat bugs");}public void sleep_ways(){System.out.println("Birds sleep on branch");}public void say_ways(){System.out.println("Birds usually sing");}}