Syntax analyser to show success using Flex and Bison

Question

I am trying to make a syntax analyzer that will recognize a valid statement and will print success upon doing so. However, after making the Lex and Yacc files, I keep getting errors in my Yacc file which says:

In function 'yyparse'fofo.y: In function 'yyparse':
fofo.y:13:5: error: stray '\223' in program
fofo.y:13:5: error: stray '' in program
fofo.y:13:16: error: 'n' undeclared (first use in this function)
fofo.y:13:16: note: each undeclared identifier is reported only once for each function it appears in
fofo.y:13:18: error: expected ')' before 'Invalid'
fofo.y:13:18: error: stray '' in program
fofo.y:13:18: error: stray '\224' in program

Here's my Yacc file contents:

%{
#include <stdio.h>
%}

%start Stmt_list
%token Id Num Relop Addop Mulop Assignop Not

%%
Stmt_list    : Stmt ';' '\n'    {printf ("\n Success. \n"); exit(0);}
        | Stmt_list Stmt ';' '\n'    {printf ("\n Success. \n"); exit(0);}
        | error '\n'    {printf (“\n Invalid. \n”); exit(1);}
        ;

Stmt    : Variable Assignop Expression
    ;

Variable    : Id
        | Id '['Expression']'
        ;

Expression    : Simple_expression
        | Simple_expression Relop Simple_expression
        ;

Simple_expression    : Term
            | Simple_expression Addop Term
            ;

Term    : Factor
    | Term Mulop Factor
    ;

Factor    : Id
    | Num
    | '('Expression')'
    | Id '['Expression']'
    | Not Factor
    ;

%%

#include"lex.yy.c"

int main()
{
    yyparse();
    yylex();

}

yyerror(char *s)
{
    printf("\nError\n");
}

Answer 1

The errors come from having some non ASCII characters in the text (which probably come from pasting text from a Word file), on line 13, as the error message indicated:

        | error '\n'    {printf (“\n Invalid. \n”); exit(1);}
                                 ^              ^
                                 |              |
                                 `--------------`------------   The error is here!

Note the quotation characters are different to the line above, and should be edited to be:

        | error '\n'    {printf ("\n Invalid. \n"); exit(1);}

I also added some white space around your tokens. For example, on these lines:

        | Id '['Expression']'
    | '('Expression')' 
    | Id '['Expression']'

which I changed to:

        | Id '[' Expression ']'
    | '(' Expression ')' 
    | Id '[' Expression ']'

I also note you are calling the C function 'exit' but have not declared it properly. You need the following line in your header:

#include <stdlib.h>

It then seemed to build OK for me.