Iterator_Class.h

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#pragma once
#ifndef __ITERATOR_CLASS_H__
#define __ITERATOR_CLASS_H__
 
#include <algorithm>
#include <memory>
 
#include "helpers/stringlist.h"
 
namespace DesignPatternExamples_cpp
{
 
    class ItemPair
    {
    public:
        std::string Key;
        std::string Value;
 
        ItemPair()
        {
        }
 
 
        ItemPair(std::string key, std::string value)
            : Key(key)
            , Value(value)
        {
        }
    };
 
 
    template <typename TItemType>
    struct IIterator
    {
        virtual ~IIterator() {}
 
        virtual void Reset() = 0;
 
        virtual bool Next(TItemType& item) = 0;
    };
 
 
    template <typename TItemType>
    class Iterator : public IIterator<TItemType>
    {
    private:
        TItemType* _items;
 
        size_t _numItems;
 
        size_t _index;
 
    public:
        Iterator(TItemType* items, size_t numItems)
            : _items(nullptr)
            , _numItems(numItems)
            , _index(0)
        {
            _items = new TItemType[numItems];
            std::copy(items, items + numItems, _items);
        }
 
        ~Iterator()
        {
            delete[] _items;
        }
 
        bool Next(TItemType& item)
        {
            bool retrieved_item = true;
            if (_index < _numItems)
            {
                item = _items[_index];
                ++_index;
            }
            else
            {
                retrieved_item = false;
            }
            return retrieved_item;
        }
 
        void Reset() override
        {
            _index = 0;
        }
    };
 
 
    class IteratorContainer_Class
    {
    public:
        std::shared_ptr<IIterator<ItemPair>> GetItems();
 
        std::shared_ptr<IIterator<std::string>> GetKeys();
 
        std::shared_ptr<IIterator<std::string>> GetValues();
    };
 
} // end namespace
 
#endif // __ITERATOR_CLASS_H__