Dynamic Allocation (Arrays) | Visual Studio vs Dev-C++

[sasauke]

Hi, guys. I couldn't find any information about this after googling for a while (blame my googling skills), so I thought I'd just ask.

So, here's the deal. In Dev-C++ (which I think uses the GCC compiler) the following would compile correct without error:

(And now that I checked, it compiles without error in "http://cpp.sh/" too)

#include <iostream>

int main()
{
	int size;
	std::cin >> size;
	
	int arr[size];
	return 0;
}

While of course, the C++ standard obvious doesn't allow you to declare an array of a non-constant size and it doesn't work in Visual Studio, which instead would have you dynamically allocate memory for it:

#include <iostream>

int main()
{
	int size;
	std::cin >> size;
	
	int *arr = new int[size];
        
        delete[] arr;
	return 0;
}

My question is, if anyone knows, what exactly happens in Dev-C++ and why does it even work?

[MiiNiPaa]

what exactly happens in Dev-C++ and why does it even work?

It is GNU extension bringing C99 VLA into C++.

I suggest to explicitely set standard to standard C++ and not gnu extention in compiler options and compile with -pedantic-errors flag (which disallows standard violations)

[sasauke]

Ahh, that makes a lot of sense. After playing a bit with the settings, I managed to fix it. Thanks!