testinterface.java

很好的一本书《JAVA设计模式》的随书源码5

/* File Name：TestInterface.java
 * 这是关于接口的应用实例，用来说明接口的概念及用法。
 */
interface Shapes {
	abstract double GetArea(); //面积
	abstract double GetPeri(); //周长
}
class Square implements Shapes {
	public int width,height; //正方形的宽和高
	Square(int width,int height) {
		this.width=width;
		this.height=height;
	}
	public double GetArea() { //正方形的面积
		return(width*height);
	}
	public double GetPeri() { //正方形的周长
		return(2*width+2*height);
	}
}
class Circle implements Shapes {
	public int width,height;
	public double r; //圆的半径
	Circle(int width,int height) {
		this.width=width;
		this.height=height;
		r=(double)width/2.0;
	}
	public double GetArea() {
		return(r*r*3.1415);
	}
	public double GetPeri() {
		return(2*3.1415*r);
	}
}
class TestInterface {
	public static void main(String[] args) {
		Square NewSquare=new Square(35,35);
		Circle NewCircle=new Circle(35,35);
		System.out.println("正方形的面积："+NewSquare.GetArea());
		System.out.println("正方形的周长："+NewSquare.GetPeri());
		System.out.println("圆的面积："+NewCircle.GetArea());
		System.out.println("圆的周长："+NewCircle.GetPeri());
	}
}