• Advertisement
Sign in to follow this  

Can someone tell me why this won't compile?(to do with strings, arrays, pointers)

This topic is 1804 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

For some reason this won't compile. This isn't the first time that something hasn't worked from this book so I suspect it's a tiny typo that is messing up the whole thing. Can someone explain to me why this doesn't compile? I'm just starting to deal with strings so I don't know how to call a function from within a string.

 

#include <stdio.h>

main ()

{ int str_number;

for (str_number = 0; str_number < 13; str_number++)
   {
   printf ("%s", menutext(str_number));
   }
}

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

char *menutext(n)
int n;

{
  static char *t[] =
   {
   "  -------------------------------------- \n",
   " |            ++ MENU ++                |\n",
   " |           ~~~~~~~~~~~~               |\n",
   " |     (1) Edit Defaults                |\n",
   " |     (2) Print Charge Sheet           |\n",
   " |     (3) Print Log Sheet              |\n",
   " |     (4) Bill Calculator              |\n",
   " |     (q) Quit                         |\n",
   " |                                      |\n",
   " |                                      |\n",
   " |     Please Enter Choice              |\n",
   " |                                      |\n",
   "  -------------------------------------- \n"
   };
return (t[n]);
}



I get an error on line 15: char *menutext(n)

 

C:\Documents and Settings\Gary II\Desktop\cprog.c|15|error: conflicting types for 'menutext'|

 

Share this post


Link to post
Share on other sites
Advertisement
The book must be really old.

It is using a K&R dialect of C that is long dead.

It likely won't compile on any compiler written to the standards of the last 13 years.

Share this post


Link to post
Share on other sites

You can't have parentheses in a variable name... char *menutext(n) is meaningless in standard C. If you want an array of character arrays, you need char* menutext[n] with the appropriate initialization code. Also, you forgot a semicolon. Also, menutext is declared after it is used, so it won't work. Also, everything after main isn't in a function, so you can't return from it.

 

Looks like old C code.

 

EDIT: I thought the menutext was a global variable - turns out its actually a function, look at Hodgman's post below for the translation.

Edited by Bacterius

Share this post


Link to post
Share on other sites
As above, that code does not resemble modern C. I guess it translates like:
#include <stdio.h>

char *menutext(int n)
{
  static char *t[] =
   {
   "  -------------------------------------- \n",
   " |            ++ MENU ++                |\n",
   " |           ~~~~~~~~~~~~               |\n",
   " |     (1) Edit Defaults                |\n",
   " |     (2) Print Charge Sheet           |\n",
   " |     (3) Print Log Sheet              |\n",
   " |     (4) Bill Calculator              |\n",
   " |     (q) Quit                         |\n",
   " |                                      |\n",
   " |                                      |\n",
   " |     Please Enter Choice              |\n",
   " |                                      |\n",
   "  -------------------------------------- \n"
   };
  return (t[n]);
}

int main()
{
  for (int str_number = 0; str_number < 13; str_number++)
  {
    printf ("%s", menutext(str_number));
  }
}

Share this post


Link to post
Share on other sites

Well crap, could someone recommend a website with a c reference that is up to date? I have been using K & R (lol). What is a good website to be learning from? Also, could anyone recommend some up-to-date books on c that are really good?

Share this post


Link to post
Share on other sites
C Unleashed by Heathfield is pretty good, although it isn't really an introductory book. There are probably newer books, but for several years that was one of the best covering the c99 standard.

Share this post


Link to post
Share on other sites

The problem, by the way, is that menutext needs to be declared before it is used. This can be done by copying the first line of the function (up to the ;), above main, or by moving the whole function. Otherwise the default return type is int, which does not match the definition.

 

The K&R style parameter definition on menutext is valid C90 code, but I'm not sure if they removed it in later standards. It's not modern practice regardless. Similarly, it's good practice to write "int main()", even though int is assumed.

Share this post


Link to post
Share on other sites

The K&R style parameter definition on menutext is valid C90 code, but I'm not sure if they removed it in later standards. It's not modern practice regardless. Similarly, it's good practice to write "int main()", even though int is assumed.

Both were removed in the C99 standard.

Share this post


Link to post
Share on other sites

If you're starting fresh - why start with c? I'd recommend you jump straight to c++ or c#.

And no - you don't need to know c to learn c++.

Share this post


Link to post
Share on other sites

For some reason this won't compile. This isn't the first time that something hasn't worked from this book so I suspect it's a tiny typo that is messing up the whole thing. Can someone explain to me why this doesn't compile? I'm just starting to deal with strings so I don't know how to call a function from within a string.

 

#include <stdio.h>

main ()

{ int str_number;

for (str_number = 0; str_number < 13; str_number++)
   {
   printf ("%s", menutext(str_number));
   }
}

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

char *menutext(n)
int n;

{
  static char *t[] =
   {
   "  -------------------------------------- \n",
   " |            ++ MENU ++                |\n",
   " |           ~~~~~~~~~~~~               |\n",
   " |     (1) Edit Defaults                |\n",
   " |     (2) Print Charge Sheet           |\n",
   " |     (3) Print Log Sheet              |\n",
   " |     (4) Bill Calculator              |\n",
   " |     (q) Quit                         |\n",
   " |                                      |\n",
   " |                                      |\n",
   " |     Please Enter Choice              |\n",
   " |                                      |\n",
   "  -------------------------------------- \n"
   };
return (t[n]);
}



I get an error on line 15: char *menutext(n)

 

C:\Documents and Settings\Gary II\Desktop\cprog.c|15|error: conflicting types for 'menutext'|

char *menutext(n)   um... where's your ;

I'm sure other people have their points too, but that was the first thing that cought my eye, and the compiler did say... that line was causing you the problem.

As already mentioned, his code is a valid C90 function definition written in K&R style. It's not a variable.

Share this post


Link to post
Share on other sites

His compiler reads it just fine. The error says "conflicting types for 'menutext'". It's complaining that menutext was implicitly declared to return int, but is defined to return char *.

 

I'm not saying that anyone should use K&R style C, but that's not the cause of the problem here.

Share this post


Link to post
Share on other sites

His compiler reads it just fine. The error says "conflicting types for 'menutext'". It's complaining that menutext was implicitly declared to return int, but is defined to return char *.

 

I'm not saying that anyone should use K&R style C, but that's not the cause of the problem here.

 

This I can accept.  Thank you sir.  As stated before, you are a well inteligent human being and I'm glad I learned something from you. smile.png

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement