I have a question regarding about declaring a new array with non-constant variable, like the following.

int main(int argc, char** argv)
{
int N = atoi(argv[1]);
int array[N];
}

As you see above, the program receives the size of the array to be created via main's argument. It's compiled successfully.

I used to program like this in C (I think its standard is some kind of C99, I am not sure about the name, sorry.) and the source file is compiled unsuccessfully.

So I guess it's about the compiler's using of standard C/C++ used in compiling process.

My question is that according to above, Is C99 (not sure, for the name) standard is abandoned already or making less popular until now? As I found on many modern linux system that I can use the code above and be able to compile successfully.

Thanks

Variable length arrays are part of C99. They do not exist in C++. Use std::vector anyway instead. It's not that C99 is abandoned, it's that C and C++ are different languages.

In previous discussions, the consensus seems to be that this C99 feature is not valid according to the C++ standard but is supported in C++ by GCC and a few other compilers.

I haven't either looked it up in the C++ standard to verify that it isn't supported (but I'm confident it is not supported) nor looked it up in GCC documentation to see how the non standard support is documented.

Okay, I know now that the topic should goes down to compiler's standard level.

Thanks for your quick reply.

No. the OP said it did compile in C++ but not in C.

I will get back to this asap.
Thanks for replies.

Generally speaking, storage-classes like std::vector (and their ilk...) are considerably more versatile than anything you could cook-up by hand.

The concept is simply that the "index" is used as a key to find the value being sought. The class takes care of all the (very efficient) management of storage, locating values, iterating through values and so on. It is a superior, and generalized, solution to the problem in most cases.

Usually, you care that the values are stored, and not how they are stored...