JAVA 第四章第一部分程序.doc

示例程序4-1 Rectangle类public class Retangle public Retangle(double l, double w) length = l; width = w; public double calcPerimeter() return 2 * (length + width); public double calcArea() return length * width; public String toString() return 长为 + length + 宽为 + width + 的长方形; protected double length; private double width;示例程序4-2 Square类public class Square extends Retangle public Square(double side) super(side,side); public double calcPerimeter() return length * 4; public String toString() return 边长为 + length + 的正方形; 示例程序4-3 几何形状的测试程序public class ShapeTest public static void main(String args) Retangle retangle = new Retangle(10.0, 20.0); Square square = new Square(10.0); System.out.println(retangle + 周长： + retangle.calcPerimeter(); System.out.println(retangle + 面积： + retangle.calcArea(); System.out.println(square + 周长： + square.calcPerimeter(); System.out.println(square + 面积： + square.calcArea(); 示例程序4-4 Berrypublic class Berry extends Fruit public Berry(String fname, int in) super(fname, in); public int gain() int g ; if (input200) g = super.gain()-200; /种植浆果类则需要另外缴纳200元的许可证费用 else g = 0; System.out.println(fruitName + 投入 + input + 净收益 + g); return g; 示例程序4-5 CitrusFruitpublic class CitrusFruit extends Fruit public CitrusFruit(String fname, int in) super(fname, in); public int gain() int g = input * 3; / 种植柑橘类净收益是投入的3倍 System.out.println(fruitName + 投入 + input + 净收益 + g); return g; 示例程序4-6 TropicalFruitpublic class TropicalFruit extends Fruit public TropicalFruit (String fname, int in) super(fname, in); public int gain() int g = super.gain(); System.out.println(fruitName + 投入 + input + 净收益 + g); return g; 示例程序4-7 Gardenerpublic class Gardener public static void main(String args) Gardener gardensys = new Gardener(张三); gardensys.work(); public Gardener(String name) gardenerName = name; public void work() System.out.println(gardenerName + 开始工作); plant(); gain(); private void plant() System.out.println(); fruits0 = new TropicalFruit(香蕉, 1000); fruits1 = new Berry(葡萄, 2000); fruits2 = new TropicalFruit(菠萝, 2000); fruits3 = new Berry(草莓, 1000); fruits4 = new CitrusFruit(橘子, 1000); for (int i = 0; i fruits.length; i+) fruitsi.grow(); fruitsi.harvest(); System.out.println(); private void gain() int sum = 0; /统计收益 for (int i = 0; i fruits.length; i+) su