CODEWITHSUNDEEP
c++arraysstack
Rutkay Karabulak
Rutkay Karabulak

Reputation: 115

Array type int[] is not assignable

I am implementing an ADT Stack using an array. I want to doubling the size of the array when the stack is full.

const int MAX_SIZE = 6 // max size of array stack
template<class ItemType>
class ArrayStack: public StackInterface<ItemType>{
private:
    ItemType items[MAX_SIZE]; // Array of stack items
    int top; // index of top
    int itemCount; // Amount of items in stack
    int maxsize;

This is my push method:

template<class ItemType>
bool ArrayStack<ItemType>::push(const ItemType& newEntry){
    if(itemCount == maxsize){ // resize array
        cout << "resizing an array..." << endl; // just for testing
        ItemType* oldArray = items; // old array to be deleted
        ItemType* newItems = new ItemType[2*maxsize];

        for(int i=0; i<maxsize; i++){
            newItems[i] = oldArray[i]; // copying all array items
        }
        delete[] oldArray; // deallocate
        maxsize = maxsize * 2; // doubling max size
        items = newItems; <- I'm getting error from this code
    } // end if

    // Stack is not full
    top++;
    items[top] = newEntry;
    itemCount++;
    return true;
}

I'm getting this error while I'm trying to double the size of the array:

error: array type 'int [6]' is not assignable
items = newItems;

How can I solve this?

Upvotes: 0

Views: 5310

Answers (1)

Remy Lebeau
Remy Lebeau

Reputation: 597101

ItemType items[MAX_SIZE]; is a fixed array. You can't resize it, you can't reallocate it, and you certainly can't assign an ItemType* pointer to it.

For what you are attempting to do, items needs to be an ItemType* pointer instead of an ItemType[] array:

template<class ItemType>
class ArrayStack: public StackInterface<ItemType>{
private:
    ItemType *items; // Array of stack items
    ...
};

Don't forget to initialize items in your constructor(s), and call delete[] items; in the destructor, and also implement proper copy/move constructors and copy/move assignment operators, per the Rule of 3/5/0.

Upvotes: 1

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