As the name suggests, a C++ built-in array is zero or more items of data of the same type. In C++, square brackets are used to declare arrays and to access array elements:
int squares[4];
for (int i = 0; i < 4; ++i)
{
squares[i] = i * i;
}The squares variable is an array of integers. The first line allocates enough memory for four integers and then the for loop initializes the memory with the first four squares. The memory allocated by the compiler from the stack is contiguous and the items in the array are sequential, so the memory location of squares[3] is sizeof(int) following on from squares[2]. Since the array is created on the stack, the size of the array is an instruction to the compiler; this is not dynamic allocation, so the size has to be a constant.
There is a potential problem here: the size of the array is mentioned twice, once in the declaration and then again in the for loop. If you use two different values, then you may initialize...