Question

I started to use Lex for my homework. In my Lex file, I always meet errors when go to first line of Rules Section. I have tested on sample code in books.

Here is the errors that Flex throw :

1 Error: Parse error at line

2 Description: Badly formed macro definition.

And here is my code.

int num_lines = 0, num_chars = 0;
%%
\n ++num_lines; ++num_chars;     // error here 
. ++num_chars;
%%
main()
{
yylex();
printf( "# of lines = %d, # of chars = %d\n",
num_lines, num_chars );
}

Thanks 🙂

Answer 1

Try

%{
int num_lines = 0, num_chars = 0;
%}

%%
...