Lexical Analyzer Using Flex

%{
    #include<stdio.h>
    int others = 0;
    int keyword = 0;
    int id = 0;
%}

%%
"int"|"double"|"float"|"char"|"do"|"while"|"main"|"return"|"printf"|"scanf"|"include"|"stdio.h" {
keyword++;
printf("\'%s\' is a keyword\n",yytext);}

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


. {}
%%

int main()
{
    yyin = fopen("input.c","r");

    yylex();
    printf("Number of identifier is %d\n", id);
    printf("Number of keyword is %d\n", keyword);
    return 0;
}


int yywrap()
{
   return 1;
}