合成演示.java

用java实现电工上的矩形波合成演示

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class 合成演示 extends Applet implements ActionListener 
{ 

	/**
	 * 
	 */
	private static final long	serialVersionUID	= 1L;
	
	
	public double calculater(int n,double m)
	{	
		 if(n == 1)
			 return Math.sin(m/25); 
		 else
			 return Math.sin((2*n-1)*m/25)/(2*n-1) + calculater(--n,m);
		 /*
		  *   1/(2*n-1)*Math.sin((2*n-1)*m/25)出现致命错误
		  *   m/25是对X坐标进行放大作用
		  */
	}
	int Um = 50;
    Button draw;  
    int n; 
    public void init() 
    { 
    	draw  = new Button("画图"); 
        add(draw);  
        draw.addActionListener(this); 
     } 
     public void actionPerformed(ActionEvent e) 
     { 
    	 if(e.getSource() == draw) 
    	 { 
    		     		 
       	     for (n=1;n<=13;n++)
       	     {
       	    	 Graphics g = getGraphics(); 
       	    	 update(g);
       	    	 /*
       	    	  * 以信号通知此Applet区域必须被更新 
                  * update(Graphics );
       	    	  */
       	    	 g.drawLine(0, 200, 550, 200);
      		     g.drawLine(78, 0, 78, 400);
          	     g.drawString("演示",10,10);
          	     if (n==13)
    	    		  n=500;//数值跳跃实现清楚变化
       	    	 g.drawString(Integer.toString(n),10,30);
       	    	 /*
       	    	  * 强制将Int类型转换为String类型
       	    	  * 相关转换 Long.toString(n)
       	    	 */
       	    	 for (int i = 0; i<500; i++) 
    		     { 
       	    		 if(i >= 78 )
       	    		 {
       	    			 int x = i;
       	    			 double m = x*1.0;
       	    			 int y = (int)(4*Um/3.14*calculater(n,m)+200); 
       	    			 g.drawString(".", x, y); 
    			     }
    		     } 
      	    	 for (int a = 0; a<20000; a++)
      	    		 for (int b = 0; b<20000; b++)
      	    		 {
      	    			 int c = a<b ? a:b; 
      	    		 } 
      	    	 /*
      	    	  * 延时
      	    	  */
       	     }
    	  }
     }
}