Why do I need a dynamic array?

[elkinscoder]

I'm trying to understand the need for dynamic arrays. My understanding is that this shouldn't work, but it does. Can anyone explain this to me?

Thanks!

  #include <iostream>

using namespace std;

int main ()
{

int arrsize;

cout << "Enter array size: ";
cin >> arrsize;

int a [arrsize];

for (int i = 0; i < arrsize; i++){
    cout << "Enter array values: ";
    cin >> a [i];}
 
for (int i = 0; i < arrsize; i++)
    cout << a [i];

return 0;

}

[maeriden]

Assuming you're referring to the fact that you're declaring a runtime-sized array like a fixed-size array, it was nonstandard. Compilers supported this as extensions to the language.
IIRC it was standardized in C++14
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3497.html

[jlb]

Actually this "feature" didn't make it into the standard. VLA are still not supported by the current standards, and hopefully never will be. If you want this "feature" I recommend using std::vector.

Now after saying the above, several compilers support this "feature" as a compiler specific option, which is why the program is compiling.