Accept both integers and floats in a bison grammar - grammar

Question

This question is attached to this post https://stackoverflow.com/questions/42848197/bison-flex-cannot-print-out-result?noredirect=1#comment72805876_42848197
this time I try to make my calculator program accepts both integers and floats numbers.
Thank you.
Here is my code
Flex:
%{
#include <stdio.h>
#include "f1.tab.h"
%}
integer [1-9][0-9]*|0
float [0-9]+\.[0-9]+
%%
{integer} { yylval.ival = atoi(yytext); return INT; }
{float} { yylval.fval = atof(yytext); return FLOAT; }
. { return yytext[0]; }
%%
Bison :
%{
#include <stdio.h>
%}
%union {
int ival;
float fval;
}
%token <ival> INT
%token <fval> FLOAT
%type <fval> exp
%type <fval> fac
%type <fval> f
%%
input: line
| input line
;
line: exp ';' { printf("%d\n", $1); };
exp: fac { $$ = $1; }
| exp '+' fac { $$ = $1 + $3; }
| exp '-' fac { $$ = $1 - $3; }
;
fac: f
| fac '*' f { $$ = $1 * $3; }
| fac '/' f { $$ = $1 / $3; }
;
f: INT | FLOAT;
%%
main(int argc, char **argv) {
yyparse();
}
yyerror(char *s) {
fprintf(stderr, "error: %s\n", s);
}

Answer 1

Bison tells you exactly what the problem is:
parser.y:32.4-6: warning: type clash on default action: <fval> != <ival> [-Wother]
f: INT | FLOAT;
^^^
The default action for the rule f: INT copies an ivar to an fvar without any sort of conversion (basically, copying via union). To fix it, you need to insert a conversion:
f: INT { $$ = (double)$1; }