classparameterdemo.java

Java语言程序设计-源代码（第二部分）和课程相对应的提供了一些用于学习理解的代码设计

class Rectangle{
int width,height;
public Rectangle(int w,int h){
	   width=w;
	   height=h;
}
}
class Circle{
double radius;
public Circle(double r){
	   radius=r;
}
}
public class ClassParameterDemo{
public static void main(String args[]){
	   ClassParameterDemo cp=new ClassParameterDemo();
	   Rectangle r=new Rectangle(10,20);
	   System.out.println("Before:Rectangle width="+r.width+",height="+r.height);
	   System.out.println("Rectangle area="+cp.area(r));
	   System.out.println("After:Rectangle width="+r.width+",height="+r.height);
	   Circle c=new Circle(90);
	   System.out.println("Before:Circle radius="+c.radius);
	   System.out.println("Circle area="+cp.area(c));
	   System.out.println("After:Circle radius="+c.radius);
}
double area(Circle c){
	   c.radius+=10;
	   return Math.PI*c.radius*c.radius;
}
double area(Rectangle r){
	   r.width+=1;
	   r.height+=1;
	   return r.width*r.height;
}
}