compilation error in Code Blocks and it runs normally in visual studio

Ab

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Oct 12, 2016, 10:51:29 PM10/12/16

to

template <typename elementType = int, int numberOfElements = 5>
class Array
{
//some code
private:
// the number of objects currently instantiated
static size_t arrayCount;
};

// class Array_include.h
#include "Array.h" // Array class definition
using namespace std;

// initializing the template static member arrayCount
template <typename elementType, int numberOfElements>
size_t Array<elementType, numberOfElements>::arrayCount = 0;

// ^^^ code block (using GCC compiler) gave me compilation error, and in
//visual studio it worked without any issues, does anyone know why?

Ian Collins

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Oct 13, 2016, 12:11:03 AM10/13/16

to

On 10/13/16 03:49 PM, Ab wrote:
> template <typename elementType = int, int numberOfElements = 5>
> class Array
> {
> //some code
> private:
> // the number of objects currently instantiated
> static size_t arrayCount;
> };
>
>
> // class Array_include.h
> #include "Array.h" // Array class definition
> using namespace std;

In a header?? No!

> // initializing the template static member arrayCount
> template <typename elementType, int numberOfElements>
> size_t Array<elementType, numberOfElements>::arrayCount = 0;
>
> // ^^^ code block (using GCC compiler) gave me compilation error, and in
> //visual studio it worked without any issues, does anyone know why?

What was the error?

--
Ian

mark

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Oct 13, 2016, 4:47:55 AM10/13/16

to

You should post the error. Maybe an include for size_t is missing. It's
used in quite a few headers, so an explicit include is usually not needed.

Alf P. Steinbach

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Oct 13, 2016, 10:40:23 AM10/13/16

to

On 13.10.2016 04:49, Ab wrote:
> template <typename elementType = int, int numberOfElements = 5>
> class Array
> {
> //some code
> private:
> // the number of objects currently instantiated
> static size_t arrayCount;
> };

This will give you one `arrayCount` for each used combination of
template parameter values.

> // class Array_include.h
> #include "Array.h" // Array class definition
> using namespace std;

Don't ever do this (in the global namespace) in a header.

> // initializing the template static member arrayCount
> template <typename elementType, int numberOfElements>
> size_t Array<elementType, numberOfElements>::arrayCount = 0;
>
> // ^^^ code block (using GCC compiler) gave me compilation error, and in
> //visual studio it worked without any issues, does anyone know why?

Readers can /guess/ that you've not include a header that defines
`size_t` in the global namespace.

The primary such header is `<stddef.h>`.

But really, why t.f. are you posting without quoting the error message,
and without a complete, minimal example that reproduces the error?

• • •

See the old FAQ's “How do I post a question about code that doesn't work
correctly?” e.g. as mirrored at <url:
http://www.dietmar-kuehl.de/mirror/c++-faq/how-to-post.html#faq-5.8>

Cheers, & hth.,

- Alf

Louis Krupp

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Oct 13, 2016, 12:44:50 PM10/13/16

to

It's all part of the learning process. Brevity might be the soul of
wit, but it needs to be fine-tuned to the situation. It took me a
while to catch on.

Louis