Need a little Help Please

**Mike1982** · 10-10-2007

Getting two errors and warning when compiling this code any help would be great.

Code:

#include <stdio.h>
#define SONG  "Say It Aint So"
#define SHOW  "Survivorman"
int menu (void);
void song (void);
void show (void);
int QUIT(void);
int main(void)
   {
   char choice;
   choice = menu();   /* get user's first selection */

   while(choice != QUIT)
   {
      switch(choice)
      {
         case SHOW:  show();
                     break;
         case SONG:  song();
                     break;
         default:    printf("Oops!  An invalid choice slipped through.  ");
                     printf("Please try again.\n");
      }
      choice = menu();  /* get user's subsequent selections */
   }

   printf("Bye bye!\n");

   /* These next 3 lines are helpful if your program doesn't pause to let you
      see the output.  (Not required.)
   */
   printf("Press Enter to end the program.\n");
   fflush(stdin);
   getchar();

   return 0;
}

int menu(void)
{
   int option;

       printf("Learn about me! Please select from the menu\n\n");
       printf("1. Learn the name of my favourite show\n");
       printf("2. Learn the first line of my favorite song\n\n");
       printf("0. Quit this program\n\n");
       printf("Enter your choice: ");

   while( (scanf(" %d", &option) != 1)  /* non-numeric input */
          || (option < 0)               /* number too small */
          || (option > 2))              /* number too large */
   {
      fflush(stdin);                    /* clear bad data from buffer */
      printf("That selection isn't valid.  Please try again.\n");
      printf("Your choice?  ");
   }
   return option;
}

void song(void)
{
   printf(" %d\n", SONG);
}

void show(void)
{
   printf(" %d\n", SHOW);
}

**dwks** · 10-10-2007

You'll get a lot more help if you actually post the error messages that you get.

Besides, with my warning level turned up, I get a lot more than two errors and warnings.

Code:

twoerrors.c: In function ‘main’:
twoerrors.c:13: warning: comparison between pointer and integer
twoerrors.c:17: error: case label does not reduce to an integer constant
twoerrors.c:19: error: case label does not reduce to an integer constant
twoerrors.c: In function ‘song’:
twoerrors.c:62: warning: format ‘&#37;d’ expects type ‘int’, but argument 2 has type ‘char *’
twoerrors.c: In function ‘show’:
twoerrors.c:67: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘char *’

The main thing is that you have a fundamental problem with your switch statement. Case label values can only be integers. They cannot be pointers, strings, or floating-point numbers.

Oh yes, and don't use fflush(stdin), it's non-standard. See the FAQ.

**robwhit** · 10-10-2007

fflush(stdin); /* clear bad data from buffer */

see faq

while(choice != QUIT)

QUIT is a function pointer.

**hk_mp5kpdw** · 10-10-2007

Originally Posted by Mike1982

Getting two errors and warning when compiling this code any help would be great.

Well... what are they? Are we supposed to guess?

Code:

int QUIT(void);
int main(void)
   {
   char choice;
   choice = menu();   /* get user's first selection */

   while(choice != QUIT)

QUIT is a function, when you use it in your code you must make a call to the function... that requires the use of parenthesis:

Code:

while(choice != QUIT())

Code:

#define SONG  "Say It Aint So"
#define SHOW  "Survivorman"

...

void song(void)
{
   printf(" %d\n", SONG);
}

void show(void)
{
   printf(" %d\n", SHOW);
}

Perhaps you meant %s which is for strings? %d is for use in displaying integers. Also...

Code:

case SHOW:  show();
    break;
case SONG:  song();

Those cannot be in a case statement, only integral types are allowed, not string literals.

Code:

fflush(stdin);

fflush of input streams is undefined. There are other ways to clear the input buffer. Check the FAQ.

**Mike1982** · 10-10-2007

Sorry about that guys The warning and errors I am getting are

Code:

case label dose not reduce to an integer constant

Code:

case label dose not reduce to an integer constant

Code:

warning: comparison between pointer and interger

Code:

warning: unreachable code at beginning of switch statement

Code:

#include <stdio.h>
#define SONG  "Say It Aint So"
#define SHOW  "Survivorman"
int menu (void);
void song (void);
void show (void);
int QUIT(void);
int main(void)
   {
   char choice;
   choice = menu();   /* get user's first selection */

   while(choice != QUIT)
   {
      switch(choice)
      {
         case SHOW:  show();
                     break;
         case SONG:  song();
                     break;
         default:    printf("Oops!  An invalid choice slipped through.  ");
                     printf("Please try again.\n");
      }
      choice = menu();  /* get user's subsequent selections */
   }

   printf("Bye bye!\n");

   /* These next 3 lines are helpful if your program doesn't pause to let you
      see the output.  (Not required.)
   */
   printf("Press Enter to end the program.\n");
   fflush(stdin);
   getchar();

   return 0;
}

int menu(void)
{
   int option;

       printf("Learn about me! Please select from the menu\n\n");
       printf("1. Learn the name of my favourite show\n");
       printf("2. Learn the first line of my favorite song\n\n");
       printf("0. Quit this program\n\n");
       printf("Enter your choice: ");

   while( (scanf(" %d", &option) != 1)  /* non-numeric input */
          || (option < 0)               /* number too small */
          || (option > 2))              /* number too large */
   {
   }
   return option;
}

void song(void)
{
   printf(" %s\n", SONG);
}

void show(void)
{
   printf(" %s\n", SHOW);
}

**matsp** · 10-10-2007

Yes, so a "case label" is what's after case in a switch statement - and it needs to be something that can be expressed as an integer. Do you think "Say It Aint So" is an integer?

"warning: comparison between pointer and interger" - this is fairly obvious, except that you probably don't realize that "choice != QUIT" is a comparison to an pointer... QUIT is a function, and when it's not having parenthesis after it, it means that you want to take the address of (pointer to) the function - and that shouldn't be compared with an integer, according to the compiler [and I think the compiler is right in this case].

--
Mats

**Mike1982** · 10-10-2007

Ya I think I have to re think this whole thing and start from scratch thanks for everyones help

Originally Posted by matsp

Yes, so a "case label" is what's after case in a switch statement - and it needs to be something that can be expressed as an integer. Do you think "Say It Aint So" is an integer?

"warning: comparison between pointer and interger" - this is fairly obvious, except that you probably don't realize that "choice != QUIT" is a comparison to an pointer... QUIT is a function, and when it's not having parenthesis after it, it means that you want to take the address of (pointer to) the function - and that shouldn't be compared with an integer, according to the compiler [and I think the compiler is right in this case].

--
Mats

**dwks** · 10-10-2007

In other words, SHOW and SONG need to be 1 and 2, respectively, because that's what the user will be entering. Then you probably want some separate #defines for the messages, which will be printed in song() and show().

**Mike1982** · 10-10-2007

Thanks dwks that helps I am starting to get it

Originally Posted by dwks

In other words, SHOW and SONG need to be 1 and 2, respectively, because that's what the user will be entering. Then you probably want some separate #defines for the messages, which will be printed in song() and show().

**Mike1982** · 10-10-2007

Ok it complies now but crashes when I run it

I guess compliers don't know everything I can screw up lol

Code:

#include <stdio.h>
#define SONG  1
#define SHOW  2
#define QUIT  0
int menu (void);
void song (void);
void show (void);
int main(void)
   {
   char choice;
   choice = menu();   /* get user's first selection */

   while(choice != QUIT)
   {
      switch(choice)
      {
         case SHOW:  show();
                     break;
         case SONG:  song();
                     break;
         default:    printf("Oops!  An invalid choice slipped through.  ");
                     printf("Please try again.\n");
      }
      choice = menu();  /* get user's subsequent selections */
   }

   printf("Bye bye!\n");



   return 0;
}

int menu(void)
{
   int option;

       printf("Learn about me! Please select from the menu\n\n");
       printf("1. Learn the name of my favourite show\n");
       printf("2. Learn the first line of my favorite song\n\n");
       printf("0. Quit this program\n\n");
       printf("Enter your choice: ");

   while( (scanf(" &#37;d", &option) != 1)  /* non-numeric input */
          || (option < 0)               /* number too small */
          || (option > 2))              /* number too large */

   return option;
}

void song(void)
{
   printf(" %s\n", SONG);
}

void show(void)
{
   printf(" %s\n", SHOW);
}

**matsp** · 10-10-2007

Maybe you want to use a different #define name for your "I like this song" part? Trying to printf a string with a constant of 2 isn't going to work.

Also, if you add -Wall to your line when you compile, it will give you more info about things that you may be doing wrong (in this case, it will say something like "format %s expects a char *, but given integer".

No, compilers don't discover ALL the stupid things we can do - only some of the easier to determine and common mistakes [and many less common mistakes - but only because the compiler can't cope, rather than because it's "wrong"].

--
Mats

**dwks** · 10-10-2007

Code:

void song(void)
{
   printf(" &#37;s\n", SONG);
}

void show(void)
{
   printf(" %s\n", SHOW);
}

SONG and SHOW are integers. You need some separate messages. I'd hard-code the messages in song() and show() -- you're already hard-coding the function calls.

BTW, your compiler should warn you about this. Mine does. I'd turn up the warning level if I were you. Are you using Dev-C++?

**Mike1982** · 10-10-2007

Yes using Dev-C++. By hard-code do you mean add define statements for 'song'
and 'show'

Thanks for all the help

Originally Posted by dwks

Code:

void song(void)
{
   printf(" &#37;s\n", SONG);
}

void show(void)
{
   printf(" %s\n", SHOW);
}

SONG and SHOW are integers. You need some separate messages. I'd hard-code the messages in song() and show() -- you're already hard-coding the function calls.

BTW, your compiler should warn you about this. Mine does. I'd turn up the warning level if I were you. Are you using Dev-C++?

**dwks** · 10-10-2007

I meant that you could probably get away with

Code:

void song(void)
{
   printf(" Say It Aint So\n");
}

void show(void)
{
   printf(" Survivorman\n");
}

But you could, of course, create separate #defines for the messages. SONG_TEXT and SHOW_TEXT, say.

In Dev-C++, go to Compiler Options and add -W -Wall to the extra compiler options text dialog. You'll get a lot more warnings that way.

**Mike1982** · 10-10-2007

Ah ok thanks I think I will use #defines. I will also try to figure out how to turn up warning levels in Dev-C++. I will post my results

Thanks

Originally Posted by dwks

I meant that you could probably get away with

Code:

void song(void)
{
   printf(" Say It Aint So\n");
}

void show(void)
{
   printf(" Survivorman\n");
}

But you could, of course, create separate #defines for the messages. SONG_TEXT and SHOW_TEXT, say.

In Dev-C++, go to Compiler Options and add -W -Wall to the extra compiler options text dialog. You'll get a lot more warnings that way.

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