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#include  
#include  
#include  
#include  
#include  
#define NULL 0 
 
FILE *fp; 
char cbuffer; 
char *key[8]={"DO","BEGIN","ELSE","END","IF","THEN","VAR","WHILE"}; 
char *border[6]={",",";",":=",".","(",")"}; 
char *arithmetic[4]={"+","-","*","/"}; 
char *relation[6]={"<","<=","=",">",">=","<>"}; 
char *consts[20]; 
char *label[20]; 
int constnum=0,labelnum=0; 
 
int search(char searchchar[],int wordtype) 
     { 
     int i=0; 
     switch (wordtype) { 
       case 1:for (i=0;i<=7;i++) 
		  { 
		   if (strcmp(key[i],searchchar)==0) 
		     return(i+1); 
		  }; 
 
       case 2:{for (i=0;i<=5;i++) 
		  { 
		   if (strcmp(border[i],searchchar)==0) 
		      return(i+1); 
		  }; 
	       return(0); 
	      } 
 
       case 3:{for (i=0;i<=3;i++) 
		  { 
		   if (strcmp(arithmetic[i],searchchar)==0) 
		      { 
		       return(i+1); 
		      }; 
		  }; 
	      return(0); 
	      }; 
 
       case 4:{for (i=0;i<=5;i++) 
		  { 
		   if (strcmp(relation[i],searchchar)==0) 
		      { 
		       return(i+1); 
		      }; 
		  }; 
	       return(0); 
	      }; 
 
       case 5:{for (i=0;i<=constnum;i++) 
		  { 
		   if (strcmp(consts[i],searchchar)==0) 
		       { 
			return(i+1); 
		       }; 
		  } 
	      consts[i-1]=(char *)malloc(sizeof(searchchar)); 
	      strcpy(consts[i-1],searchchar); 
	      constnum++; 
	      return(i); 
	      }; 
 
       case 6:{for (i=0;i<=labelnum;i++) 
		  { 
		     if (strcmp(label[i],searchchar)==0) 
		       { 
			return(i+1); 
		       }; 
		  } 
	      label[i-1]=(char *)malloc(sizeof(searchchar)); 
	      strcpy(label[i-1],searchchar); 
	      labelnum++; 
	      return(i); 
	      }; 
 
      } 
 
 
     } 
 
 
char alphaprocess(char buffer) 
     { 
      int atype; 
      int i=-1; 
      char alphatp[20]; 
      while ((isalpha(buffer))||(isdigit(buffer))) 
	    { 
	    alphatp[++i]=buffer; 
	    buffer=fgetc(fp); 
	    }; 
      alphatp[i+1]='\0'; 
      if (atype=search(alphatp,1)) 
	 printf("%s (1,%d)\n",alphatp,atype-1); 
      else 
	 { 
	 atype=search(alphatp,6); 
	 printf("%s (6,%d)\n",alphatp,atype-1); 
	 }; 
      return(buffer); 
      } 
 
char digitprocess(char buffer) 
     { 
      int i=-1; 
      char digittp[20]; 
      int dtype; 
      while ((isdigit(buffer))) 
	    { 
	    digittp[++i]=buffer; 
	    buffer=fgetc(fp); 
	    } 
      digittp[i+1]='\0'; 
      dtype=search(digittp,5); 
      printf("%s (5,%d)\n",digittp,dtype-1); 
      return(buffer); 
     } 
 
char otherprocess(char buffer) 
     { 
 
      int i=-1; 
      char othertp[20]; 
      int otype,otypetp; 
      othertp[0]=buffer; 
      othertp[1]='\0'; 
      if (otype=search(othertp,3)) 
	 { 
	 printf("%s (3,%d)\n",othertp,otype-1); 
	 buffer=fgetc(fp); 
	 goto out; 
	 }; 
 
      if (otype=search(othertp,4)) 
	      { 
	      buffer=fgetc(fp); 
	      othertp[1]=buffer; 
	      othertp[2]='\0'; 
	      if (otypetp=search(othertp,4)) 
		 { 
		 printf("%s (4,%d)\n",othertp,otypetp-1); 
		 goto out; 
		 } 
	      else 
		 othertp[1]='\0'; 
		 printf("%s (4,%d)\n",othertp,otype-1); 
		 goto out; 
	      }; 
 
      if (buffer==':') 
	      { 
	      buffer=fgetc(fp); 
	      if (buffer=='=') 
		 printf(":= (2,2)\n"); 
		 buffer=fgetc(fp); 
		 goto out; 
	      } 
	   else 
	      { 
	      if (otype=search(othertp,2)) 
		 { 
		 printf("%s (2,%d)\n",othertp,otype-1); 
		 buffer=fgetc(fp); 
		 goto out; 
		 } 
	      }; 
 
	  if ((buffer!='\n')&&(buffer!=' ')) 
		  printf("%c error,not a word\n",buffer); 
	  buffer=fgetc(fp); 
out:      return(buffer); 
     } 
 
 
 
void main() 
     { 
     int i; 
      for (i=0;i<=20;i++) 
	  { 
	   label[i]=NULL; 
	   consts[i]=NULL; 
	  }; 
      if ((fp=fopen("\\DEMO.PAS","r"))==NULL) 
	 printf("error"); 
      else 
	{ 
	cbuffer = fgetc(fp); 
	while (cbuffer!=EOF) 
	 { 
	  if (isalpha(cbuffer)) 
	     cbuffer=alphaprocess(cbuffer); 
	  else if (isdigit(cbuffer)) 
	     cbuffer=digitprocess(cbuffer); 
	  else cbuffer=otherprocess(cbuffer); 
	  }; 
	 printf("over\n"); 
	 }; 
      }