// File: main3.C
//
// A calculator program

#include <iostream.h>
#include <iomanip.h>
#include "bstring4.h"
#include "token.h"
#include "parse.h"

main() {
   BString bs ;
   TokenStream *tkptr ;
   ETree *Tptr ;

   cout << "A calculator program.  Enter blank line to quit.\n" ;

   while (true) {
      cout << "? " ;
      cin >> bs ;

      if (bs.length() == 0) break ;

      tkptr = new TokenStream(bs) ;

      if (tkptr == NULL) {
         cerr << "Out of memory!" << endl ;
         exit(1) ;
      }

      Tptr = Parse(*tkptr) ;
      if (Tptr != NULL) {
         cout << "= " << Evaluate(*Tptr) << endl ;
      }

      delete tkptr ;
      delete Tptr ;
   }
}