program1-----> To count the no of tokens and display to the token

%{ 
#include<stdio.h>
#include<string.h>
int n = 0 ; 
%} 
 

%% 
"while"|"if"|"else" {n++;printf("\t keywords : %s", yytext);} 
 
"int"|"float" {n++;printf("\t keywords : %s", yytext);}   
 

[a-zA-Z_][a-zA-Z0-9_]* {n++;printf("\t identifier : %s", yytext);} 
 

"<="|"=="|"="|"++"|"-"|"*"|"+" {n++;printf("\t operator : %s", yytext);}
 
[(){}|, ;]    {n++;printf("\t separator : %s", yytext);} 
 

[0-9]*"."[0-9]+ {n++;printf("\t float : %s", yytext);} 
 

[0-9]+ {n++;printf("\t integer : %s", yytext);} 

"\n"  {printf("\n total no. of token = %d\n", n);} 
%% 
 
   int yywrap(void){}
int main() 
 
{ 
    yylex();
    printf("check");
         
    return 0;
     
}