%{
#define  ENDFILE  0
#define  IDENT    1
#define  INTEGER  2
#define  REAL     3

#include <math.h>

#undef yywrap
int yywrap(void) { return 1; }

extern int line_count;
extern int decimal_digit;
extern float real_num;
%}

Digit    [0-9]
Letter   [a-zA-Z]
%%

("+"|"-")?{Digit}+"."{Digit}+("E"("+"|"-"|""){Digit}+)*  {
                       /* Real Constant */ real_num = atof(yytext);
                          return REAL; }

{Digit}+                        { /* Decimal Integer */ decimal_digit = atoi(yytext);
                                    return INTEGER; }

{Letter}({Letter}|{Digit}|_)*   { /* Identifier */     return IDENT; }

[ \t]+				{ /* Skip blanks and tabs */ }

"\n"				{ /* Count lines */    line_count++; }

.				{ /* Skip all other characters */ }

<<EOF>>				{ /* End-of-file */    return ENDFILE; }
%%