Hi, I am struggling with my Yacc Program. Here are the requirements:

According to the following context-free grammar, write a yacc file as a integer calculator that can do +, -, *, /, and ^ with or without ( ).

commandexpr

exprexpr + term | exprterm | term

termterm * term2 | term / term2 | term2 |-factor

term2factor ^ term2 | factor

factor( expr ) | NUMBER

In order to run calculator on real numbers the following needs to be added in the definition section and then the rest of the program needs to be made to work on real numbers.

%token NUMBER

%union { double val;

char op; }

%type exp term factor NUMBER

%type '+' '-' '*' '/' '(' ')'

%%

THE CODE I HAVE IS:

%{ #include #include #include %}

%token NUMBER

%%

command : exp {printf("%d ",$1);} ;

exp : exp '+' term {$$ = $1 + $3;} | exp "-" term {$$ = $1 - $3;} | exp '^' term {$$ = pow($1,$3);} |'(' exp ')' term {$$ = $2;} | term {$$ = $1;} ;

term : term '*' factor {$$ = $1 * $3;} | term '/' factor {$$ = $1 / $3;} | factor {$$ = $1;} ;

factor : NUMBER {$$ = $1;} | '(' exp ')' {$$ = $2;} ;

%%

main() { return yyparse(); }

int yylex(void) { int c; while((c = getchar()) == ' '); if ( isdigit(c) ) { ungetc(c, stdin); scanf("%d",&yylval); return(NUMBER); } if ( c == ' ') return 0; return(c); }

int yyerror(char * s) { fprintf(stderr,"%s ",s); return 0; }