Problem receiving an array as pointer parameter

Question

Hi I have a trouble trying to manage a the following array. I have initialized this pointer int* coordenadasFicha = new int[2]; and I want to asign the two int asking the user for the numbers. The trouble appears when I call pedirCoordenadasFicha(coordenadasFicha); Clion recomends me cast coordenadasFicha to int** but I need to use it as a simple pointer. pedirCoordenadasFicha() basically does this:

void pedirCoordenadasFicha(int* coordenadasFicha[2]){
    std::cin >> *coordenadasFicha[0];
    std::cin >> *coordenadasFicha[1];}

All help is welcome

Answer 1

An int* (a pointer-to-int) and an int*[] (an array of pointer-to-int) are two different things. And actually, in a function parameter, int* coordenadasFicha[2] is actually passed as int** (pointer to pointer-to-int), because an array decays into a pointer to its 1st element.

In your case, you are creating coordenadasFicha as an dynamic array of ints, but your function is expecting an array of int* pointers instead.

So, to do what you are attempting, you would need to do either this:

void pedirCoordenadasFicha(int* coordenadasFicha){
    std::cin >> coordenadasFicha[0];
    std::cin >> coordenadasFicha[1];
}

int* coordenadasFicha = new int[2];
pedirCoordenadasFicha(coordenadasFicha);
...
delete[] coordenadasFicha;

Or this:

void pedirCoordenadasFicha(int* coordenadasFicha[2]){
    std::cin >> *coordenadasFicha[0];
    std::cin >> *coordenadasFicha[1];
}

int** coordenadasFicha = new int*[2];
for(int i = 0; i < 2; ++i) {
    coordenadasFicha[i] = new int;
}
pedirCoordenadasFicha(coordenadasFicha);
...
for(int i = 0; i < 2; ++i) {
    delete coordenadasFicha;
}
delete[] coordenadasFicha;

Or, just get rid of new altogether, and pass the array by reference:

void pedirCoordenadasFicha(int (&coordenadasFicha)[2]){
    std::cin >> coordenadasFicha[0];
    std::cin >> coordenadasFicha[1];
}

int coordenadasFicha[2];
pedirCoordenadasFicha(coordenadasFicha);
...