duck.java

词法分析

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.lang.*;
public class Duck extends JPanel{
JTextField mekey;
JTextField youkey;
JButton button;
String Keyword[]={"char","short","int","unsigned","long", "float","double","struct","union","void ",
		"enum","signed","const","volatile","typedef","auto","register","static","extem","break","extem ",
	"break","case ","continue","default","do","while","else","for","goto","if",
		"return","switch","while","sizeof"};


Duck()
	{
	
	mekey = new JTextField(20);
	button = new JButton("确定");
	
	button.addActionListener(new ActionListener(){
		public void actionPerformed(ActionEvent evt){
			int key;
			String text=mekey.getText();
			key=laoding(text);




if(key==0)
			youkey.setText("这什么都不是");
			else if(key==1)
			youkey.setText("求余");
			else if (key==2)
			youkey.setText("这是数字（整数)");
            else if(key==3)
			youkey.setText("这是分隔符");
			else if (key==4)
            youkey.setText("数字(浮点数)");
			else if (key==5)
			youkey.setText("这是保留字");
			else if (key==6)
			youkey.setText("????????");
			else if (key==7)
			youkey.setText("数字呢！(科学记数发的数值)");
			else if (key==8)
			youkey.setText("标志符");
			else if (key==9)
			youkey.setText("特殊字符！");
			else if (key==10)
			youkey.setText("减号");
			else if (key==11)
			youkey.setText("加号");
else if (key==12)
			youkey.setText("乘号");
else if (key==13)
			youkey.setText("除号");
else if (key==14)
			youkey.setText("附值符号");
else if (key==15)
	youkey.setText("等号");
else if(key==16)
	youkey.setText("小于");
else if (key==17)
{youkey.setText("小于等于");
}
else if (key==18)
{youkey.setText("大于");
}
else if (key==19)
{youkey.setText("大于等于");
}
else if (key==20)
{youkey.setText("逻辑与");
}
else if (key==21)
{youkey.setText("逻辑或");

}
else if (key==22)
{youkey.setText("逻辑非");
}

			else if (key==101)
			youkey.setText("非法的字符！");
			else 
				youkey.setText("这是错误的，请重新输入一下！");
			
			}
	});
	youkey = new JTextField(20);
	JPanel panel = new JPanel();
	panel.setLayout(new FlowLayout(FlowLayout.RIGHT,30,20));
	panel.add(mekey);
	panel.add(button);
	this.setLayout(new BorderLayout());
	
	this.add(panel,BorderLayout.NORTH);
	this.add(youkey,BorderLayout.SOUTH);
	
	}


	int yugaochao(String s)
	{	    int key;
			int i;
			for(i=0;i<35;i++)
		{
				if(s.equals(Keyword[i]))
			{		key=5;
					return  key;
					}
              }
             key=8;
			 return key;

	}


int  laoding(String s)
	
{ 
	char ch;
	int STATE ;
	int key=101;
	int i=0;
	int Accept=100;
	int Erro=101;
	int j=s.length();
	STATE = 0;
	if(j==0)
	return 0;

	while(STATE!=Accept){
		
		
		
		
		if(((i==j)&&((STATE==2)||(STATE==4)||(STATE==5)||(STATE==7)||(STATE==8)||(STATE==9)||(STATE==10)))||STATE==Erro)
		{

		key=STATE;
		if(STATE==8)
			{
				key=yugaochao(s);
			}
		STATE=Accept;
		
		return key;
		}
		ch=s.charAt(i);
	
i++;
System.out.println(STATE);
System.out.println(key);

		switch(STATE)
		{
			case 0:
				if(ch=='-'||ch=='+')
				{
					STATE=1;
					if((i==j)&&(ch=='-'))
					return 10;
					if((i==j)&&(ch=='+'))
					return 11;
				}
			else if (Character.isDigit(ch))
			{STATE=2;
			}
			    else if (Character.isLetter(ch))
			   STATE=8;
				else if (ch=='*'&&i==j)
					return 12;
else if(((ch==' ')||(ch=='\t')||(ch=='\n'))&&(i!=j))
   STATE=0;
				else if (ch=='/'&&i==j)
					return 13;
else if (ch=='='&&i==j)
	return 14;
else if(ch=='='&&i!=j)

	STATE= 9;
else if (ch=='%'&&i==j)
	{
		return 1;	
	}
	else if (ch=='<'&&i==j)
	{return 16;
	}
	else if (ch=='<'&&i!=j)
	{
		STATE= 10;	
	}
	else if (ch=='>'&&i==j)
	{return 18;
	}
	else if (ch=='>'&&i!=j)
	{STATE =11;
	}
	else if((ch=='&')&&(i!=j))
		STATE=12;
	else if ((ch=='|')&&(i!=j))
	{STATE=13;
	}
		else if (ch=='!'&&i==j)
	{return 22;
	}		

else if (((ch==';')||(ch ==' ')||(ch==','))&&i==j)
{return 3;
	
}






				else 
					STATE=Erro;
				break;
			case 1:
				if(Character.isDigit(ch))
				STATE=2;
				else 
				STATE=Erro;
			break;
			case 2:
				if(Character.isDigit(ch))
				STATE=2;
				else if (ch=='E'||ch=='e')
				{	STATE=5;
				}
				else if(ch=='.')
					{
					STATE=3;
					if(i==j)
						STATE=Erro;}
				else 
				STATE=Erro;
break;
			case 3:
				if(Character.isDigit(ch))
				STATE=4;
				else 
				STATE=Erro;
				break;
			case 4:
				if(Character.isDigit(ch))
				STATE=4;
				else if (ch=='E'||ch=='e')
				{	STATE=5;
				}
				else 
				STATE=Erro;
				break;
			case 5:
				if (ch=='+'||ch=='-')
				{STATE=6;
				}
				else if(Character.isDigit(ch))
				STATE=7;
				else 
				STATE=Erro;
				break;

			case 6:
					if(Character.isDigit(ch))
				STATE=7;
		
			else 
				STATE=Erro;
				break;

				case 7:
					if(Character.isDigit(ch))
				STATE=7;
				
			else 
				STATE=Erro;
				break;
				case 8:
					if(Character.isLetter(ch)||Character.isDigit(ch))
					STATE=8;
				else
					STATE=Erro;
				break;
				case 9:
					if(ch=='='&&i==j)
						return 15;
					else 
STATE=Erro;
				break;
				case 10:
					if(ch=='='&&i==j)
						return 17;
				else STATE =Erro;
				break;
				case 11:
					if(ch=='='&&i==j)
					return 19;
				else STATE = Erro;
				break;
				case 12:
					if(ch=='&'&&i==j)
					return 20;
					else STATE=Erro;
					case 13:
					if(ch=='|'&&i==j)
					return 21;
					else STATE=Erro;
				case 101:
					i=j;
				break;

			default:
					STATE=Erro;
				
			}
	}
	

return key;
	
}



	public static void main(String arg[]){
		JFrame frame = new JFrame("词法分析器");
		frame.addWindowListener(new closewindow());
		frame.getContentPane().add(new Duck());
		frame.pack();
		frame.show();
	}
	}



class closewindow extends WindowAdapter{
	public void windowClosing(WindowEvent e){
		System.exit(0);
	}
}