C++ Primer, Fifth Edition

12.2.1. new and Arrays

We ask new to allocate an array of objects by specifying the number of objects to allocate in a pair of square brackets after a type name. In this case, new allocates the requested number of objects and (assuming the allocation succeeds) returns a pointer to the first one:

// call get_size to determine how many ints to allocateint *pia = new int[get_size()]; // pia points to the first of these ints

The size inside the brackets must have integral type but need not be a constant.

We can also allocate an array by using a type alias (§ 2.5.1, p. 67) to represent an array type. In this case, we omit the brackets:

typedef int ...