qt4.java

java可以实现一些小程序的编写

class point{ 
  	int x, y;  
  	  	point( ){ this(0,0);}  
  	point(int x, int y){  this.x=x; this.y=y;   }    
  	double area( ){ return 0;}
}

class circle extends point{
   	int radius;   
   	circle(int r, int x, int y){  super(x, y);    radius=r; }      
   	double area( ){    
	  	return   Math.PI*radius*radius ;  
   	} 
} 

public class qt {
    public static void main(String args[ ]) {
	point p[ ]={new point(2,2), new circle(1,1,1) };
		
	for(int i=0;i<p.length;i++){			
		System.out.print("类名"+p[i].getClass( ).getName( ));
		System.out.print("父类"+p[i].getClass( ).getSuperclass( ));
		System.out.println("面积"+
			p[i].area( ));
		}
	}
}