Vector<T>   d = getData();
for(int loop = 0; loop < d.size(); ++loop)
{
    std::cout << d[loop];   // No need for antoher range
                            // check here as we know that loop is inside the
                            // bounds of the vector d.
}

#include <type_traits>
#include <memory>
#include <algorithm>
#include <stdexcept>
#include <iterator>

template<typename T>
class Vector
{
    public:
        using value_type        = T;
        using reference         = T&;
        using const_reference   = T const&;
        using pointer           = T*;
        using const_pointer     = T const*;
        using iterator          = T*;
        using const_iterator    = T const*;
        using riterator         = std::reverse_iterator<iterator>;
        using const_riterator   = std::reverse_iterator<const_iterator>;
        using difference_type   = std::ptrdiff_t;
        using size_type         = std::size_t;

    private:
        size_type       capacity;
        size_type       length;
        T*              buffer;

        struct Deleter
        {
            void operator()(T* buffer) const
            {
                ::operator delete(buffer);
            }
        };

    public:
        Vector(int capacity = 10)
            : capacity(capacity)
            , length(0)
            , buffer(static_cast<T*>(::operator new(sizeof(T) * capacity)))
        {}
        template<typename I>
        Vector(I begin, I end)
            : capacity(std::distance(begin, end))
            , length(0)
            , buffer(static_cast<T*>(::operator new(sizeof(T) * capacity)))
        {
            for(auto loop = begin;loop != end; ++loop)
            {
                pushBackInternal(*loop);
            }
        }
        Vector(std::initializer_list<T> const& list)
            : Vector(std::begin(list), std::end(list))
        {}
        ~Vector()
        {
            // Make sure the buffer is deleted even with exceptions
            // This will be called to release the pointer at the end
            // of scope.
            std::unique_ptr<T, Deleter>     deleter(buffer, Deleter());
            clearElements<T>();
        }
        Vector(Vector const& copy)
            : capacity(copy.length)
            , length(0)
            , buffer(static_cast<T*>(::operator new(sizeof(T) * capacity)))
        {
            try
            {
                for(int loop = 0; loop < copy.length; ++loop)
                {
                    push_back(copy.buffer[loop]);
                }
            }
            catch(...)
            {
                std::unique_ptr<T, Deleter>     deleter(buffer, Deleter());
                clearElements<T>();

                // Make sure the exceptions continue propagating after
                // the cleanup has completed.
                throw;
            }
        }
        Vector& operator=(Vector const& copy)
        {
            copyAssign<T>(copy);
            return *this;
        }
        Vector(Vector&& move) noexcept
            : capacity(0)
            , length(0)
            , buffer(nullptr)
        {
            move.swap(*this);
        }
        Vector& operator=(Vector&& move) noexcept
        {
            move.swap(*this);
            return *this;
        }
        void swap(Vector& other) noexcept
        {
            using std::swap;
            swap(capacity,      other.capacity);
            swap(length,        other.length);
            swap(buffer,        other.buffer);
        }

        // Non-Mutating functions
        size_type       size() const                      {return length;}
        bool            empty() const                     {return length == 0;}

        // Validated element access
        reference       at(size_type index)               {validateIndex(index);
                                                           return buffer[index];}
        const_reference at(size_type index) const         {validateIndex(index);
                                                           return buffer[index];}

        // Non-Validated element access
        reference       operator[](size_type index)       {return buffer[index];}
        const_reference operator[](size_type index) const {return buffer[index];}
        reference       front()                           {return buffer[0];}
        const_reference front() const                     {return buffer[0];}
        reference       back()                            {return buffer[length - 1];}
        const_reference back() const                      {return buffer[length - 1];}

        // Iterators
        iterator        begin()                           {return buffer;}
        riterator       rbegin()                          {return riterator(end());}
        const_iterator  begin() const                     {return buffer;}
        const_riterator rbegin() const                    {return const_riterator(end());}

        iterator        end()                             {return buffer + length;}
        riterator       rend()                            {return riterator(begin());}
        const_iterator  end() const                       {return buffer + length;}
        const_riterator rend() const                      {return const_riterator(begin());}

        const_iterator  cbegin() const                    {return begin();}
        const_riterator crbegin() const                   {return rbegin();}
        const_iterator  cend() const                      {return end();}
        const_riterator crend() const                     {return rend();}

        // Comparison
        bool operator!=(Vector const& rhs) const {return !(*this == rhs);}
        bool operator==(Vector const& rhs) const
        {
            return  (size() == rhs.size())
                &&  std::equal(begin(), end(), rhs.begin());
        }

        // Mutating functions
        void push_back(value_type const& value)
        {
            resizeIfRequire();
            pushBackInternal(value);
        }
        void push_back(value_type&& value)
        {
            resizeIfRequire();
            moveBackInternal(std::move(value));
        }
        template<typename... Args>
        void emplace_back(Args&&... args)
        {
            resizeIfRequire();
            emplaceBackInternal(std::move(args)...);
        }
        void pop_back()
        {
            --length;
            buffer[length].~T();
        }
        void reserve(size_type capacityUpperBound)
        {
            if (capacityUpperBound > capacity)
            {
                reserveCapacity(capacityUpperBound);
            }
        }
    private:
        void validateIndex(size_type index) const
        {
            if (index >= length)
            {
                throw std::out_of_range("Out of Range");
            }
        }

        void resizeIfRequire()
        {
            if (length == capacity)
            {
                size_type     newCapacity  = std::max(2.0, capacity * 1.5);
                reserveCapacity(newCapacity);
            }
        }
        void reserveCapacity(size_type newCapacity)
        {
            Vector<T>  tmpBuffer(newCapacity);

            simpleCopy<T>(tmpBuffer);

            tmpBuffer.swap(*this);
        }

        // Add new element to the end using placement new
        void pushBackInternal(T const& value)
        {
            new (buffer + length) T(value);
            ++length;
        }
        void moveBackInternal(T&& value)
        {
            new (buffer + length) T(std::move(value));
            ++length;
        }
        template<typename... Args>
        void emplaceBackInternal(Args&&... args)
        {
            new (buffer + length) T(std::move(args)...);
            ++length;
        }

        // Optimizations that use SFINAE to only instantiate one
        // of two versions of a function.
        //      simpleCopy()        Moves when no exceptions are guaranteed;
        //                          otherwise, copies.
        //      clearElements()     When no destructor remove loop.
        //      copyAssign()        Avoid resource allocation when no exceptions guaranteed.
        //                          ie. When copying integers, reuse the buffer if we can
        //                          to avoid expensive resource allocation.

        template<typename X>
        typename std::enable_if<std::is_nothrow_move_constructible<X>::value == false>::type
        simpleCopy(Vector<T>& dst)
        {
            std::for_each(buffer, buffer + length,
                          [&dst](T const& v){dst.pushBackInternal(v);}
                         );
        }
        template<typename X>
        typename std::enable_if<std::is_nothrow_move_constructible<X>::value == true>::type
        simpleCopy(Vector<T>& dst)
        {
            std::for_each(buffer, buffer + length,
                          [&dst](T& v){dst.moveBackInternal(std::move(v));}
                         );
        }


        template<typename X>
        typename std::enable_if<std::is_trivially_destructible<X>::value == false>::type
        clearElements()
        {
            // Call the destructor on all the members in reverse order
            for(int loop = 0; loop < length; ++loop)
            {
                // Note we destroy the elements in reverse order.
                buffer[length - 1 - loop].~T();
            }
        }

        template<typename X>
        typename std::enable_if<std::is_trivially_destructible<X>::value == true>::type
        clearElements()
        {
            // Trivially destructible objects can be reused without using the destructor.
        }

        template<typename X>
        typename std::enable_if<(std::is_nothrow_copy_constructible<X>::value
                            &&  std::is_nothrow_destructible<X>::value) == true>::type
        copyAssign(Vector<X>& copy)
        {
            // This function is only used if there is no chance of an exception being
            // thrown during destruction or copy construction of the type T.


            // Quick return for self assignment.
            if (this == &copy)
            {
                return;
            }

            if (capacity <= copy.length)
            {
                // If we have enough space to copy, then reuse the space we currently
                // have to avoid the need to perform an expensive resource allocation.

                clearElements<T>();     // Potentially does nothing (see above)
                                        // But if required will call the destructor of
                                        // all elements.

                // buffer now ready to get a copy of the data.
                length = 0;
                for(int loop = 0; loop < copy.length; ++loop)
                {
                    pushBackInternal(copy[loop]);
                }
            }
            else
            {
                // Fallback to copy and swap if we need more space anyway
                Vector<T>  tmp(copy);
                tmp.swap(*this);
            }
        }

        template<typename X>
        typename std::enable_if<(std::is_nothrow_copy_constructible<X>::value
                             &&  std::is_nothrow_destructible<X>::value) == false>::type
        copyAssign(Vector<X>& copy)
        {
            // Copy and Swap idiom
            Vector<T>  tmp(copy);
            tmp.swap(*this);
        }
};