C++: Why does int array[size] work?

Question

I have started learning c++. I read that an array's size can only be set before run and dymanic arrays can be set during runtime. So I was expecting this to fail but it didn't:

#include <iostream>

int main() {
    using namespace std;
    int size;
    cout << "enter array size:";
    cin >> size;
    int i, score[size], max; //array size set to variable doesn't fail
    cout << endl << "enter scores:\n";
    cin >> score[0];
    max = score[0];
    for (i = 1; i < size; i++)
    {
        cin >> score[i];
        if (score[i] > max)
    max = score[i];
    }
    cout << "the highest score is " << max << endl;
    return 0;
}

Is this a new feature in recent C++ compilers? Is it realising I need a dynamic array and creating that instead?

Answer 1

Probably you are using GCC compiler, it has an extension called Arrays of Variable Length.

std::vector is the real dynamic arrays in C++.

To select this standard in GCC, use the option -std=c++11; to obtain all the diagnostics required by the standard, you should also specify -pedantic (or -pedantic-errors if you want them to be errors rather than warnings).