sinapplet.java

来自「递归子程序法：对应每个非终结符语法单元编一个独立的处理过程（或子程序）。语法分析」· Java 代码 · 共 52 行

import java.awt.*;

	/** 
	 * Java语言实验参考程序
	 * Company 北京师范大学计算机系
 
	 * @author 孙一林
	 * @version 1.0
	 */
import java.awt.event.*;
import java.applet.*;
import java.awt.Graphics;

public class SinApplet extends Applet {
  boolean isStandalone = false;
  int Phase;

  double f(double x) {
    return (Math.sin(Phase + x/7) + 2) * size().height / 4;
  }
  /**Get a parameter value*/
  public String getParameter(String key, String def) {
    return isStandalone ? System.getProperty(key, def) :
      (getParameter(key) != null ? getParameter(key) : def);
  }

  /**Construct the applet*/
  public SinApplet() {
  }
  /**Initialize the applet*/
  public void init() {
    try {
      Phase = Integer.parseInt(this.getParameter("Phase", "90"));
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  /**Get parameter info*/
  public String[][] getParameterInfo() {
    String[][] pinfo =
      {
      {"Phase", "int", "Phase"},
      };
    return pinfo;
  }
  public void paint(Graphics g) {
    for (int x = 0 ; x < size().width ; x++) {
      g.drawLine(x, (int)f(x), x + 1, (int)f(x + 1));
    }
  }
}