Lex program to count the number of identifiers

//Lex program to count the number of identifiers

%{

#include<iostream.h>

int count_identifiers=0;

%}

digit[0-9]

letter[a-zA-Z_]

%%

{letter}({letter}|{digit})* {

 count_identifiers++;

}

%%

int main()

{

 yylex();

 printf("count: %d",count_identifiers);

 return 0;

} 

output: