Question

I am learning C++ and I just read about dynamic arrays and how it lets you set the length of an array during runtime rather than during compile time. However, you don’t need a dynamic array to do this. So what is the point of a dynamic array; when would you use it? I feel like I am missing something obvious so any insight is much appreciated. Thanks!

// Static binding.
int size = 0;

cout << "Enter size of array:" << endl;
cin >> size;

int array[size];

int array_length = sizeof(array) / sizeof(int);
cout << "Number of elements in array: " << array_length << endl;

// I just set the length of an array dynamically without using a dynamic array.
// So whats the point of a dynamic array then?

Answer 1

I don’t think you can do that in C++. Only C99 allows variable-length arrays.

Does this even compile? Were you talking about the vector class?

EDIT:

It does not compile in Visual Studio 2010:

1>..\main.c(207): error C2057: expected constant expression
1>..\main.c(207): error C2466: cannot allocate an array of constant size 0
1>..\main.c(207): error C2133: 'array' : unknown size
1>..\main.c(209): error C2070: 'int []': illegal sizeof operand