方法声明无效；需要返回类型

import java.awt.*;
import java.awt.event.*;
class WinndowButton extends Frame
implements ActionListener
{
   int number;
   Label 提示条;
   TextField 输入框;
   Button buttonGetNumber,buttonEnter;
    WindowButton(String s)
    {
    super(s);
    setlayout(new FlowLayout());
    buttonGetNumber=new Button("得到一个随机数");
    add(buttonGetNumber);
    提示条=new Label("输入你的猜测：",Label.CENTER);
    提示条.setBackground(color.cayn);
    输入框=new TextField("0",10);
    add(提示条);
    add(输入框);
    buttonEnter=new button("确定");
    add(buttonEnter);
    buttonEnter.addActionListener(this);
    buttonGetNumber.addActionListener(this);
    setBounds(100,100,150,150);
    setVisible(true);
    validate();
    }
          public void actionperformed(ActionEvent e)
          {
                if(e.getsource()==buttonGetNumber)
              {  number=(int)(Math.random()*100)+1;
                提示条.setText("输入你的猜测：");
              }
          else if(e.getsource()=buttonEnter)
          {
          int guess=0;
          try{
              guess=Integer.parseInt(输入框.getText());
              if(guess==number)
                  {  提示条.setText("猜对了！");
                     输入框.setText(null);
                   }
               else if(guess>number)
                    {  
                       提示条.setText("你猜大了！");
                       输入框.setText(null);
                    
                    }
                 else if(guess<number)
                  {     提示条.setText("你猜小了!"); 
                        输入框.setText(null);
                    }
                  }
              
            catch(NumberFormatException event)
            {
            提示条.setText("请输入数字字符！ ");
            }
           }
         }
}
       
       
      public class Exampleshuiji
      {
         public static void main(String args[])
         {
         WindowButton win=new WindowButton("窗口");
         }
      } 
上面是那一段代码。运行时提示错误如下！
C:\Documents and Settings\Administrator\桌面\shuiji.java:10: 方法声明无效；需要返回类型
    WindowButton(String s)
    ^谁能帮我解决下！！三Q本人菜鸟//希望能帮我解释一下！