cd1.2

%option noyywrap
%%
break|float|int|if|char|for|return|void|struct|else printf("keywords");
^[a-zA-Z_][a-zA-Z0-9_]* printf("valid identifier");
^[^a-zA-Z_]+[a-zA-Z0-9_]* printf("invalid identifier");
.;
%%

int main()
{

	yylex();

}