一个简单的计算器

				/*
				* File:   		Panel3D.java
				* Description:  Creates a panel with a three dimensional border
				*/
				import java.awt.*;
				
				class Panel3D extends Panel {
					                
				private Border3D border;     //used for drawing the border
				
				//create a full border by default
				public Panel3D() { this( Border3D.FULL_BORDER ); }
				
				public Panel3D( int type )
				{
				  	border = new Border3D( this, type );
				}
					    
				public void paint( Graphics g )
				{
					border.draw3DBorder( g );		
				}
				
				}