設計一個名為figure的圖形軟體包（package）。包中包含三角形、矩形、圓三個類。要求：（1）每個類都要構造方法併為成員設定get和set方法；（2）每個類都要有計算周長和麵積的成員方法；（3）完成該軟體包後的編碼後，在另一個包的含有main方法的類中編寫程式碼，分別使用圖形軟體包中的三個類，生成三個物件，並打印出其周長和麵積。

package figure;

public class CirCle {
    public double r;

    public CirCle() {
		this.r = 0;
	}
	public CirCle(double r) {
		this.r = r;
	}
	public double getR() {
		return r;
	}
	public void setR(double r) {
		this.r = r;
	}
	public double perimeter()//求周長函式
	{
		return Math.PI * 2 * r;
	}
	public double area()
	{
		return Math.PI * r * r;
	}
	
	
    
}
 

package figure;

public class JuXing {
    public double chang,kuan;
    public JuXing() {
		this.chang = 0;
		this.kuan = 0;
	}
	public JuXing(double chang, double kuan) {
		this.chang = chang;
		this.kuan = kuan;
	}
	public double getChang() {
		return chang;
	}
	public void setChang(double chang) {
		this.chang = chang;
	}
	public double getKuan() {
		return kuan;
	}
	public void setKuan(double kuan) {
		this.kuan = kuan;
	}
	public double perimeter()//求周長函式
	{
		return 2*(chang + kuan);
	}
	public double area()
	{
		return chang*kuan;
	}
}
 

package figure;

public class TriAngle {
    public double a,b,c;//表示三角形的三條邊
    public TriAngle() {
		this.a = 0;
		this.b = 0;
		this.c = 0;
	}
	public TriAngle(double a , double b , double c ) {
		this.a = a;
		this.b = b;
		this.c = c;
	}
	
	public double getA() {
		return a;
	}

	public void setA(int a) {
		this.a = a;
	}

	public double getB() {
		return b;
	}

	public void setB(int b) {
		this.b = b;
	}

	public double getC() {
		return c;
	}

	public void setC(int c) {
		this.c = c;
	}

	public double perimeter()//求周長函式
	{
		return a + b + c;
	}
	public double area()
	{
		double p = (a + b + c)/2;
		return Math.sqrt(p*(p-a)*(p-b)*(p-c));//海倫公式
	}
}
 

package figure_show;

import figure.CirCle;
import figure.JuXing;
import figure.TriAngle;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		TriAngle t = new TriAngle(3,4,5);
		System.out.println("三角形的周長為："+t.perimeter());
		System.out.println("三角形的面積為："+t.area());
		JuXing p = new JuXing(3,4);
		System.out.println("矩形的周長為："+p.perimeter());
		System.out.println("矩形的面積為："+p.area());
		CirCle c = new CirCle(5);
		System.out.println("圓的周長為："+c.perimeter());
		System.out.println("圓的面積為："+c.area());
	}

}