question8.java

java课程的资料以及实验的代码

abstract class Shape
{
	abstract double getArea();
	abstract double getPerim();
}

class Rectangle extends Shape
{
	private float a;
	private float b;
	public Rectangle(float a,float b)
	{
		this.a=a;
		this.b=b;
	}
	double getArea()
	{
		return(a*b);
	}
	
	double getPerim()
	{
		return(2*(a+b));
	}
}

class Circle extends Shape
{
	private float r;
	public Circle(float r)
	{
		this.r=r;
	}
	
	double getArea()
	{
		return(Math.PI*r*r);
	}
	
	double getPerim()
	{
		return(2*Math.PI*r);
	}
}

class Q8
{
	public static void main(String args[])
	{
		Rectangle rr=new Rectangle(10f,20.5f);
		System.out.println("rectangle area="+rr.getArea());
		System.out.println("rectangle perimeter="+rr.getPerim());
		
		Circle cc=new Circle(10.0f);
		System.out.println("circle area="+cc.getArea());
		System.out.println("circle perimeter="+cc.getPerim());
	}
}