Data Structures (2110211) - CP::stack

#ifndef _CP_STACK_INCLUDED
#define _CP_STACK_INCLUDED

#include <iostream>

namespace CP {
    template <typename T>
    class stack {
        protected:
            T *mData;
            size_t mSize;
            size_t mCap;

            void expand(size_t capacity) {
                T *arr = new T[capacity]();
                for (size_t i=0; i<mSize; i++) {
                    arr[i] = mData[i];
                }
                delete [] mData;
                mData = arr;
                mCap = capacity;
            }

            void ensureCapacity(size_t capacity) {
                if (capacity > mCap) {
                    size_t newCapacity = (capacity > mCap * 2) ? capacity : mCap * 2;
                    expand(newCapacity);
                }
            }
        public:
            stack() {
                mData = new T[1]();
                mCap = 1;
                mSize = 1;
            }

            stack(const stack<T> &s) {
                ensureCapacity(s.size());
                for (size_t i=0; i<s.size(); i++) {
                    this->mData[i] = s.mData[i];
                }
            }

            stack<T>& operator= (const stack<T>& other) {
                using std::swap;
                ensureCapacity(other.mCap);
                for (size_t i=0; i<other.mSize; i++) {
                    this->mData[i] = other.mData[i];
                }
                this->mSize = other.mSize;
                return *this;
            }

            ~stack() {
                delete [] mData;
            }

            bool empty() const {
                return mSize == 0;
            }

            size_t size() const {
                return mSize;
            }

            T& top() const {
                return mData[size() - 1];
            }

            void push(const T& element) {
                ensureCapacity(mCap + 1);
                mData[mSize++] = element;
            }

            void pop() {
                mSize--;
            }
    };
}
#endif