Help I can't get this simple flex/bison compiler to work

I just want it to perform simple arithmetic, but I'm doing something wrong

This is the lex file

%{
#include <stdlib.h>
#include "compile.h"
%}

%%
"+" {return PLUS;}
"-" {return MINUS;}
"*" {return TIMES;}
"/" {return DIVIDE;}
"(" {return LEFT;}
")" {return RIGHT;}
"\n" {return END;}
[0-9]+ {yylval=atoi(yytext); return NUMBER;}
[ \t]+

%%
yywrap() {
return 1;
}

and this is the bison file

%{
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "compile.h"
%}

%token NUMBER
%token PLUS
%token MINUS
%token TIMES
%token DIVIDE
%token LEFT
%token RIGHT
%token END

%start Input
%%

Input:

| Input Line
;

Line:
END
| Expression END { printf("Result: %f\n", $1); }
;


Expression:
NUMBER { $$=$1; }
| Expression PLUS Expression { $$=$1+$3; }
| Expression MINUS Expression { $$=$1-$3; }
| Expression TIMES Expression { $$=$1*$3; }
| Expression DIVIDE Expression { $$=$1/$3; }
| LEFT Expression RIGHT { $$=$2; }
;

%%

int yyerror(char *errMessage) {
printf("Trouble: %s\n",errMessage);
}

main() {
yyparse();
}

I think you can see what I'm tring to do, but when I try to compile I get "16 shift reduce conflicts" and the trouble parse error when I test it

there isnt much c++ code there.

the only thing your main does is call yyparse(), which isnt anywhere in you poorly formatted code. Please use code tags.

What is your c++ question?

Quote:

---

Originally Posted by Amleto

the only thing your main does is call yyparse(), which isnt anywhere in you poorly formatted code.

---

This is because this is not C++ or C code at all. This is bison(or yacc) BNF input format.
Maybe this yacc calculator example will prove handy ?
I am absolutely *not* the master of bison(or yacc), but there is at least one thing I noticed you failed in doing: defining operator precedences (using &#37;left, %right).

Regards,
Zachm