Incompatibilities with C for Dummies?

[Wokzombie]

The book C for Dummies 2nd Edition is has been pretty good for me for the first three chapters, but now I got to a point where I would swear that the book has it wrong, hence me posting this.

The book is written in 2004, which is pretty new in C terms. It also recommends using GCC, which is no problem whatsoever since I'm a GNU/Linux user, so I would guess the code explained, including the examples, would be correct.
Still I can't see what I would have mistyped in this simple example:

#include <stdio.h>

int main()
{
    char me[20];
    
    printf("What is your name?");
    scanf("%s",&me);
    printf("Darn glad to meet you, %s!\n",me);
    
    return(0);
} 

As far as I can see I copied it character for character, still when I try to compile it through the "gcc who.c -o who" command in GCC 4.4.1 I get this error message:

who.c: In function ‘main’:
who.c:8: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘char (*)[20]’

Is this the book giving me wrong code, or did I really miss something there?

[Tool]

Remove the & operator. Probably a typo in the book.

"me" itself is a pointer to the first array element of the array. Dereferencing it cannot be done since its just a pointer, not a ptr to ptr.

who.c:8: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘char (*)[20]’

The error says that formated string in printf expects a char pointer, and not a pointer to an array with 20 elements.

[flexo87]

[flexo@localhost ~]$ gcc who.c -o who
[flexo@localhost ~]$ ./who 
What is your name?flexo!
Darn glad to meet you, flexo!!
[flexo@localhost ~]$ gcc --version
gcc (GCC) 4.4.2 20091222 (Red Hat 4.4.2-20)
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I have no idea!

[Wokzombie]

Thanks for the advice Tool, removing the & operator shut my compiler right up.
In a few months I will come back and know what the rest is you said

Strange that it did work for you Flexo..

[quzah]

flexo87
gcc -Wall -pedantic *.c
 
Join Date: Jan 2009
Location: London
Posts: 55

Unlike his name-comment, he didn't actually compile with either -Wall or -pedantic, or he too would have had the same issue.


Quzah.

[flexo87]

flexo87
gcc -Wall -pedantic *.c
 
Join Date: Jan 2009
Location: London
Posts: 55

Unlike his name-comment, he didn't actually compile with either -Wall or -pedantic, or he too would have had the same issue.


Quzah.

Yeah you're right!!... but in any case I would have got warnings not compiling errors!! (if we have to be pedantic!)

[Wokzombie]

Strange, a few paged later the author goes a bit further into scanf() and after going through a few aspects of the scanf() function (is that the correct term?) I see this halfway through:

scanf(“%s”,&name);

There is the ampersand in the same place again. The author's explanation is this:
"The ampersand is required here to help scanf() find the location of the string variable in memory."

[MK27]

I don't think the author could believe this is correct, perhaps it is a product of cut and pasting the same mistake several times when editing.

[Wokzombie]

I don't know if you where writing the reply before I edited in the quote, but the author literaly says
"The ampersand is required here to help scanf() find the location of the string variable in memory."

That points towards an intentional act, but Tool pointed out it is incorrect and my compiler seems to agree with him.

I compiled the code in my original post with the -std=c89,c99,gnu89 and gnu99 flags. All of them give the same result.

[Salem]

Books are no more bug-free than anything else.

Even the best book on C - K&R is not without a tidy number of issues.

Expecting some cheaply produced mass market "pulp" with "dummies" in the title to be perfect is asking way too much.

> "The ampersand is required here to help scanf() find the location of the string variable in memory."
The author is clueless.
I think you've already out-grown the book and you need to find something better to learn from.

[laserlight]

I don't know if you where writing the reply before I edited in the quote, but the author literaly says
"The ampersand is required here to help scanf() find the location of the string variable in memory."

Yes, then the author is dead wrong. Even more remarkably, this is not mentioned in the errata.

[Wokzombie]

Hrm, I think I'll just have to dump C For Dummies.
Another book I'm interested in is Beginning C, by Ivor Horton