Unused variable

[DocHaydn]

Hello,
I'm a learner. Compiler: MinGW Developer Studio, O/S:Win'98SE.

The program is a mail manager, taken from my "C"
book:"C by Example". On compilation, I'm getting the
warning:"Unused variable'list'"; on the line:"struct
mail_struct list[MAX];", just after,int main(){.

This variable is not used anywhere else in the book;
in my program, so I'm stumped. If I remove it, I get
the error:"syntax error before token."

It seems as though, it's a use,or remove issue.
How do I safely remove this variable; or where in my
program do I use it?

I'll only post the offending part of the program.

Thank you.

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>



/*Global structure of name and address.*/

struct mail_struct
{
   char name[25];
   char address[25];
   char city[20];
   char province[20];
   char zipcode[7];        /* Extra NULL character.*/
   char code [10];         /*For additional expansion.*/

};

/*Global file pointer.*/

FILE *fp;

/*Defined constants.*/
/*MAX is the total number of names allowed in memory for reading
mailing lists.*/

#define MAX 250
#define FILENAME "ADDRESS.DAT"

/*Prototype all of the program's functions.*/

int main(void);
void disp_menu(void);
void enter_name(void);
int change_name(void);
void print_name(void);
void flush_newline(char *line);
void add_to_file(struct mail_struct item);
char pr_data(struct mail_struct item);
void get_new_item(struct mail_struct *item);
void pause_sc(void);
int getzip(char zipcode[]);


/**********************************************************/

int main()
{
   struct mail_struct list [MAX]; /*Warning is here.*/
   int ch;

   do
   {
      disp_menu();
      scanf(" %d", &ch);
      while(getchar()!='\n');

      switch(ch)
      {
         case(1) : {enter_name();
               break;}
         case(2) : {change_name();
               break;}
         case(3) : {print_name();
               break;}
         case(4) :  {break;}
         default :  {printf("You need to enter");
                     printf(" 1 through 4");
                     break;}
    }
  }
  while(ch != 4);
  getchar();

  return 0;
}

 

[Salem]

Dunno - I can remove it quite happily and it compiles as expected.

--

 

[cpjust]

Doesn't the "syntax error before token" tell you which token it's complaining about? It it complaining about the int ch; line?

You can probably get rid of the "unused variable" error by just typeing: list; after you declare it, but since it's not used you should really remove it.

 

[Diancecht]

I think you made some other changes and they're making the compiler to fail. Repeat the process and you'll get the errors away.

Cheers,
Dian

 

[ArkM]

Unused/unreferenced variable is a warning, not an error. The list var does not referenced in main(), it's true. You may discard this var definition in main() safety.
But if you remove struct mail_struct type declaration too, your compiler will detect an error (like described in the original post) because of struct mail_struct type used in the functions prototype list. For example, add_to_file wants this type declaration (are you sure type but not type*?).
Syntax error before token is a typical message from one-pass compilers when they detect undeclared struct/union (or class in C++) arg/var in declaration lists...