Yacc programming in windows

download required software : click here

write a yacc program and save it as prg1.y:

%{
// yacc program to implement the grammar
/*
S->(S)
  |a
*/    
#include <stdio.h>
#include <stdlib.h>
%}

%%
Stmt1 : Stmt1 '\n' {   printf ("\n.. Valid Expression.. \n");
                               exit(0);  }
         | S
         | error  {  printf ("\n..Invalid ..\n");
                        exit(0); }
         ;
S : '(' S ')'
   | 'a'
  ;
%%

main ( )
{
  printf("Enter a string to validate : ");
  yyparse ( );
}

yylex()
{    int ch;            
      while(ch=getchar())  
      return ch;      
}
         
yyerror(char *s)
{
    printf( "%s", s );
}

compile the program using the command: bison prg1.y

with this command a C program is created in the current folder with name prg1.tab.c

now compile and run the C program: