How could I allocate 1D array by using pointer to pointer (int **)

Question

What is the difference in

void AllocateArray(int **arr,int size)

and:

void AllocateArray(int *arr,int size)

I have to allocate only 1D array by using both, and what is difference?

Answer 1

I suppose the usage should be:

int* arr;
AllocateArray(&arr, 10);
// array has been allocated, use arr[0]...arr[9].
// ...
delete[] arr;  // don't forget this

According to the function's name, it might allocate the memory for the array. Such as:

void AllocateArray(int **arr,int size) {
    *arr = new int[size];
}

The second AllocateArray's parameter(i.e. int *arr) is passed by value, that means even the memory is allocated inside the function, it has nothing to do with the outside variable.