Introduction to Java Programming编程题11.1<The triangle class>

运行结果：

Triangle: side1 = 1.0 side2 = 1.0 side3 = 1.0color: greenfilled: falseTriangle: side1 = 1.0 side2 = 1.5 side3 = 1.0color: yellowfilled: true

GeometricObject.java

package Uber;public class GeometricObject {    private String color = "green";    private boolean filled = false;    public GeometricObject() {}    public GeometricObject(String color, boolean filled) {        this.color = color;        this.filled = true;    }    public String getColor() {return color;}    public boolean getFilled() {return filled;}    public void setColor(String color) {this.color = color;}    public void setFilled(boolean filled) {this.filled = filled;}}

Triangle.java

package Uber;public class Triangle extends GeometricObject {    private double side1;    private double side2;    private double side3;    public Triangle() {side1 = side2 = side3 = 1;}    public Triangle(double side1, double side2, double side3) {        this.side1 = side1;        this.side2 = side2;        this.side3 = side3;    }    public void setSide(double side1, double side2, double side3) {        this.side1 = side1;        this.side2 = side2;        this.side3 = side3;    }    public double getArea() {        double p = (side1 + side2 + side3) / 2;        return Math.sqrt(p * (p - side1) * (p - side2) * (p - side3));    }    public double getPerimeter() {return side1 + side2 + side3;}    public String toStr() {        return "Triangle: side1 = " + side1 + " side2 = " + side2 + " side3 = " + side3;    }}

TestTraingle.java

package Uber;public class TestTraingle {    public static void main(String[] args) {        Triangle one = new Triangle();        System.out.println(one.toStr() + "\ncolor: " + one.getColor() + "\nfilled: " + one.getFilled());        one.setColor("yellow");        one.setFilled(true);        one.setSide(1, 1.5, 1);        System.out.println(one.toStr() + "\ncolor: " + one.getColor() + "\nfilled: " + one.getFilled());    }}