Simple pointer problem...

[DavidDobson]

Hi everyone

I an trying to get the size of a string that is being held inside a variable defined as a pointer, I keep getting either one or two from the following code, where as I want to get 11 (number of letters in “hello world”)

Can someone help me out please,

many thanks

David

#include <stdio.h>
#include <stdlib.h>
int size = 0;
char *message;
int main()
{
    message = "hello world";
    size = sizeof(message);
    printf("size: %i", size);
    return 0;
}

[laserlight]

message is a pointer, so sizeof(message) returns the size of a pointer. #include <string.h> and use strlen(message) instead.

By the way, unless there is some special need to make size and message global variables, make them local variables.

[QuantumPete]

you want strlen() not sizeof().

QuantumPete

[DavidDobson]

Ah! fantastic - thanks

[matsp]

I keep getting either one or two from the following code

Are you by any chance using Turbo C++? If so, I would suggest that you get a compiler produced in this decade. 10+ years old may be fine for Whiskey, Cognac, etc, but it's not really a quality mark on a compiler.

The Microsoft Visual Studio C++ Express Edition is available for free, and does everything that Turbo C++ does, and lots more.

Or if, you don't like Microsoft, Code::Blocks or Dev-C++ are two packages that use gcc as a compiler. gcc is the compiler used to build Linux, and it's a really great open-source compiler [meaning that you can get the source code for that compiler - but it's NOT even close to beginner code, so I would suggest that you don't try that unless you have plenty of spare time and already know LOTS of C (and a bit about compiler design and such)].

--
Mats

[Elysia]

Also, if you plan on storing string literals in pointer, I suggest you make them const char. This explain it somewhat more clearly:
http://cpwiki.sourceforge.net/Common...kes_and_errors

[ari]

be careful!!
you are not allocating the memory

[matsp]

be careful!!
you are not allocating the memory

And neither is there any need for that in the code posted.

--
Mats