JAVA 第四章第一部分程序.doc
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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 Berry
public 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 CitrusFruit
public 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 TropicalFruit
public class TropicalFruit extends Fruit {
public TropicalFruit (String fname, int in) {
super(fname, in);
}
public int gain() {
in
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