How is memory allocated for an array dynamically in C++?int* arr = new int[10];int arr = new int[10];int arr[10] = new int;int* arr = alloc int[10];

In C++, dynamic memory allocation for an array can be done using the 'new' operator. Here is the step by step process:

1. Declare a pointer: First, you need to declare a pointer of the type of array you want to create. For example, if you want to create an array of integers, you would declare an integer pointer.

int* arr;

2. Allocate memory: Next, you use the 'new' operator to allocate memory for the array. The 'new' operator returns a pointer to the first element of the array. You need to specify the number of elements that the array should hold inside square brackets.

arr = new int[10];

In this case, memory for 10 integers is allocated and the address of the first element is assigned to the 'arr' pointer. Now, 'arr' can be used like a normal array.

The other lines of code you provided are incorrect:

• int arr = new int[10]; is incorrect because 'arr' is not a pointer.
• int arr[10] = new int; is incorrect because you're trying to assign a pointer to an array.
• int* arr = alloc int[10]; is incorrect because 'alloc' is not a valid keyword in C++. You should use 'new' instead.