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

Java图形对象与三角形类设计

最新推荐文章于 2021-02-21 00:02:26 发布

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本文介绍了一个简单的Java程序设计案例，其中包括定义几何对象类GeometricObject及继承自它的三角形类Triangle。通过具体实例展示了如何创建、设置属性以及获取三角形的特性。

运行结果：

Triangle: side1 = 1.0 side2 = 1.0 side3 = 1.0
color: green
filled: false
Triangle: side1 = 1.0 side2 = 1.5 side3 = 1.0
color: yellow
filled: 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());
    }
}