Question

C++ newb here. I’m trying to write my own implementation of an array using only pointers, and I’ve hit a wall I don’t know how to get over.

My constructor throws this error

array.cpp:40:35: error: invalid conversion from ‘int*’ to ‘int’ [-fpermissive]

When my array initializes I want it to free up all the spaces in the array for ints.

Array::Array(int theSize){
size = theSize;
int *arrayPointer = new int; 
int index = 0;
while(theSize > index){
  *(arrayPointer + index) = new int; //This is the trouble line.
  ++index;
 }
}

What am I doing wrong stackoverflow?

Answer 1

arrayPointer points to a single int, it does not point to an array of int*, which this line would require:

*(arrayPointer + index) = new int;

but the type of *(arrayPointer + index) is an int, hence the compiler error.

To allocate an array of int:

int* arrayPointer = new int[size];

If this is intended to initialise a member variable then:

arrayPointer = new int[size];

otherwise arrayPointer would be local to the constructor. As the class now has a dynamically allocated member you need to either implement both copy constructor and assignment operator or prevent copying (see What is The Rule of Three?). Remember to delete[] arrayPointer in the destructor.

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Just mentioning std::vector<int>, even though this is a learning exercise.