www.pudn.com > bycksj.rar > aaa.cpp

 
//(1)S->aAcBe  
//(2)A->b  
//(3)A->Ab  
//(4)B->d  
#include   
#include   
#include   
#define stack_size 20  
#define stackincrement 10  
int p=0,q=0,zh,sh,x;  
char Vn[3]={'S','A','B'};   //非终结符  
char Vt[6]={'a','c','e','b','d','#'};   //终结符  
typedef struct {  
    char *bottom;  
    char *top;  
    int size;  
// char data[stack_size];  
}stack;  
int Initstack(stack &s)        //初始化栈  
{  
   s.bottom=(char *)malloc(stack_size*sizeof(char));  
   if(!s.bottom) exit(-1);  
   s.top=s.bottom;  
   s.size=stack_size;  
   return(1);  
}  
int push(stack &s,char e)      //入栈  
{  
 //int i;  
   if(s.top-s.bottom>=s.size){  
      s.bottom=(char *)realloc(s.bottom,(stack_size+stackincrement)*sizeof(char));  
      if(!s.bottom) exit(-1);  
      s.top=s.bottom+s.size;  
      s.size+=stackincrement;  
     
   }  
   *s.top++=e;  
      
    cout<=s.size){  
      s.bottom=(char *)realloc(s.bottom,(stack_size+stackincrement)*sizeof(char));  
      if(!s.bottom) exit(-1);  
      s.top=s.bottom+s.size;  
      s.size+=stackincrement;  
     
   }  
   *s.top++=e;  
      
    cout<>st[0];  
   while(st[i]!=';') 
   {  
      i++;  
      cin>>st[i];  
   }    
   Initstack(s);  
   Initstack(t);  
   push(s,'#');  
   push2(t,0);  
   cout<<"\t";  
   while(ok==1) 
   {  
     ch=st[index];  
     index++;  
     cout<0&&action(q,6,y)<10) 
	  {  
          push(s,ch);  
          push2(t,zh);  
         // q=zh;  
      }  
       if(action(q,6,y)>10&&action(q,6,y)<20) 
	   {  
          switch(zh)  
          {  
		     case 11:  
	    	 for(i=0;i<5;i++) 
			 { 
				 pop(s,&y);pop2(t,&x); 
			 }  
          push(s,'S');  
             
          pop2(t,&e);  
          push2(t,e);  
          go(e,3,'S');  //查询GOTO表  
          push2(t,sh);  //替换后的数字  
          index--;  
          break;  
          case 12: pop(s,&y);pop2(t,&x);  
          push(s,'A');  
          pop2(t,&e);  
          push2(t,e);  
          go(e,3,'A');  
          push2(t,sh);  
          index--;  
          break;  
          case 13: 
				 pop(s,&y);  
                 pop(s,&y);  
                 pop2(t,&x);  
                 pop2(t,&x);  
                 push(s,'A');  
                 pop2(t,&e);  
                 push2(t,e);  
                 go(e,3,'A');  
                 push2(t,sh);  
                 index--;  
                 break;  
           case 14:  
				  pop(s,&y); 
				  pop2(t,&x);  
                  push(s,'B');    
			      pop2(t,&e);  
                  push2(t,e);  
                  go(e,3,'B');  
                  push2(t,sh);  
                  index--;  
                  break;  
           }  
	   }  
  if(action(q,6,y)==20)  
  { 
	  cout<<"分析成功"<