Ytukyg

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





    deleteptrArr1;

    return 0;



}

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;

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?