Question

I had a computer science class at school and our teacher was talking about dynamic memory allocation and why

cin>>size;
int array[size]; // According to him this should result in a compiler error

this shouldn’t work and instead we were supposed to use:

int *p, size;
cin>>size;
p = new int[size]
...
delete[] p;

My question is, why does the first example work if you cannot declare dynamically arrays like that?

UPDATE: All tests are made in GNU GCC Compliler and the code above is inside the main function

Answer 1

You’re using a non-standard compiler, that supports variable length arrays. Your professor is right, int array[size] shouldn’t compile.

Your professor is also wrong telling you to use p = new int[size]. What he should do is tell you to use std::vector<int> p(size). (okay, for educational purposes this is OK) 🙂