Question

Firstly I wanted to say this is a HW assignment and I just have questions in regards to the errors I’m facing

I made a vector template with an insert function that adds a data_type to the end of a dynamic array. This is what I have currently.

// Insert the value at the specified index by moving the tail
// when Size = Capacity the Vector has to be reallocated first 
// to accomate the new element
void Insert(const DATA_TYPE& value, int index){

    // If the Capacity is not large enough then ...
    // allocate large vector
    if (Size >= Capacity){
        // 0. Let's boost the capacity
         Capacity += CAPACITY_BOOST;
        // 1. Allocate new larger vector
         DATA_TYPE* newData = new DATA_TYPE[Capacity];

        // 2. Copy from old Data into the newData
         for( int i=0; i< Size; i++)
                newData[i] = Data[i];

        // 3. Delete the old Data
         delete[] Data;

        // 4. Replace old Data-pointer with the newData pointer
        Data = newData;
    }

    // Move the tail
    for(int i=index; i<Size;i++){
        Data[i+1] = Data[i];
    }

    // Insert
    Data[index] = value;
    Size++;

}
DATA_TYPE& operator[] (int index) const{
    return *this[index];
}

Note: Using Private Variables: Size, Capacity, Data(stores the dynamic array)
I’m pretty sure I’ve implemented the add or push_back function correctly. The problem is when ever I try to cout something like “cout << a[1]; ” I get an error.

while compiling class template member function 'int &Vector<DATA_TYPE>::operator [](int) const'
      with
      [
          DATA_TYPE=int
      ]
see reference to class template instantiation 'Vector<DATA_TYPE>' being compiled
     with
     [
          DATA_TYPE=int
      ]
error C2440: 'return' : cannot convert from 'const Vector<DATA_TYPE>' to 'int &'
    with
     [
        DATA_TYPE=int
      ]

Answer 1

There should be 2 versions of your operator[]:

const DATA_TYPE& operator[] (int index) const;
DATA_TYPE& operator[] (int index);

What you have is a weird combination of the two.

You should also be returning

return Data[index];

Returning (*this)[index]; would result in an infinite recursive call (well, not infinite, you’ll get a stackoverflow before that).