Assigning values to all the elements of a dynamically allocated pointer array?

Question

I have a pointer array (ptrArr1) with two elements. I want the pointer array to be dynamically allocated. I can assign an address to the first element of the pointer array just fine, but I do not know how to assign an address to the second element of the pointer array. I do not wish to use any STLs or other precoded functions. I'm am doing this exercise to enhance my understanding of pointers. Thank you.

int main()
{
    int one = 1;
    int two = 2;
    int *ptrArr1 = new int[2];
    ptrArr1 = &one;
    ptrArr1[1] = &two;  //does not work
    ptrArr1 + 1 = &two; // does not work


    delete[]ptrArr1;
    return 0;

}

Answer 1

There is a difference between an array of integers and an array of pointers to int. In your case ptrArr1 is a pointer to an array of integers with space for two integers. Therefore you can only assign an int to ptrArr1[1] = 2 but not an address. Compare

int xs[] = { 1, 2, 3 };    // an array of integers

int y0 = 42;
int *ys[] = { &y0, &y0 };  // an array of pointers to integers

Now you could also have pointers pointing to the first element of xs resp. ys:

int *ptr_xs = &xs[0];
int **ptr_ys = &ys[0];

// which can be simplified to:
int *ptr_xs = xs;
int **ptr_ys = ys;

For the simplification step you should look into What is array decaying?

Answer 2

You have an int array, not a pointer array. You can create a pointer array using

int **ptrArr1 = new int*[2];

and then assign the pointers to each pointer in the array:

ptrArr1[0] = &one;
ptrArr1[1] = &two;