findarea.java

使用Swing编写的记事本

class Figure {
	double dim1;
	double dim2;
	Figure(double a,double b) {
		dim1=a;
		dim2=b;
	}
	double area() {
		System.out.println("Area for Figure is undefined");
		return 0;
	}
}

class Rectangle extends Figure {
	Rectangle(double a,double b) {
		super(a,b);
	}
	double area(){
		System.out.println("Inside Area for Rectangle.");
		return dim1*dim2;
	}
}

class Triangle extends Figure {
	Triangle(double a,double b) {
		super(a,b);
	}
	double area(){
		System.out.println("Inside Area for Triangle.");
		return dim1*dim2/2;
	}
}

public class FindArea {
	public static void main(String args[]) {
		Figure f=new Figure(10,10);
		Rectangle r=new Rectangle(9,5);
		Triangle t=new Triangle(10,8);
		Figure figure;
		figure=r;
		System.out.println("Area is:" + figure.area());
		figure=t;
		System.out.println("Area is:" + figure.area());
		figure=f;
		System.out.println("Area is:" + figure.area());
	}
}