process.java

一个简单的文法分析算法

import java.io.*;
import java.awt.*;
import javax.swing.*;
public class Process 
{
    
    private char[] end=new char[0];
      public Process()
    {
      
       end=new char[5];
         end[0]='+';
        end[1]='-';
        end[2]='*';
         end[3]='/';   
    }
   public static void main(String args[])
    
    {
        
        
        String string=" ";
       String s=" "; 
       NewString str;
       LinkNode[] link=new LinkNode[0];
       LinkNode[] templink;
       LinkNode l=new LinkNode();
       char[] c=new char[4];
       char[] temp;
       int m=1,n=0,p=0;
       int count=1;
       for(;;)
       {
       if(c[0]=='e'&&c[1]=='x'&&c[2]=='i'&&c[3]=='t')  System.exit(0);
       else 
       
       {
       System.out.println("请输入一个文法,或输入end进入目标字符串输入: ");
        try{
            BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
            string=in.readLine();
            
          }catch(IOException e){}
          c=string.toCharArray();
         if(c[0]=='e'&&c[1]=='n'&&c[2]=='d')
             break;
         else {
             templink=link;
             link=new LinkNode[m];
             for(int j=0;j<link.length;j++)
                  link[j]=new LinkNode();
             str=new NewString(string);
                 
             for(int j=0;j<m-1 ;j++)
                { link[j]=templink[j];
                    }
               link[m-1].initLinkNode(str);
                m++;
                      }
        }
        }
       System.out.println("输入目标字符串：");
       try{
            BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
            string=in.readLine();
            
          }catch(IOException e){}
         temp=string.toCharArray();
       PTree ptree=new PTree();
       ptree.BuildTree(link);
       
        }
}