Daviddoria: Created page with 'This example demonstrates what you have to implement to create an STL iterator. ==CustomIterator.cpp== #include template struct Poin…'

2012-01-02T16:19:32Z

Created page with 'This example demonstrates what you have to implement to create an STL iterator. ==CustomIterator.cpp== <source lang="cpp"> #include <iterator> template <typename T> struct Poin…'

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This example demonstrates what you have to implement to create an STL iterator.

==CustomIterator.cpp==
<source lang="cpp">
#include <iterator>

template <typename T>
struct PointedType;

template <typename T>
struct PointedType<T*>
{
typedef T value_type;
};

using namespace std;

template <typename InputIterator>
struct DerefIterator
{
typedef input_iterator_tag iterator_category;
typedef typename PointedType<
typename iterator_traits<InputIterator>::value_type>::value_type
value_type;
typedef typename iterator_traits<InputIterator>::difference_type
difference_type;
typedef value_type* pointer;
typedef value_type& reference;

public:
explicit DerefIterator(const InputIterator& ii)
: it(ii) {}

// Returns the object pointed by the object referenced by it
reference operator*() const { return **it; }
pointer operator->() const { return *it; }

DerefIterator& operator++()
{
++it;
return *this;
}

DerefIterator operator++(int)
{
DerefIterator tmp = *this;
++it;
return tmp;
}

bool equals(const DerefIterator<InputIterator> & di) const
{
return di.it == it;
}

private:
InputIterator it;
};

// Equality functions

template <typename InputIterator>
inline bool operator==(const DerefIterator<InputIterator>& di1,
const DerefIterator<InputIterator>& di2)
{
return di1.equals(di2);
}

template <typename InputIterator>
inline bool operator!=(const DerefIterator<InputIterator>& di1,
const DerefIterator<InputIterator>& di2)
{
return ! (di1 == di2);
}

//Helper function

template <typename InputIterator>
DerefIterator<InputIterator> deref_iterator(const InputIterator& ii)
{
return DerefIterator<InputIterator>(ii);
}

int main()
{
return 0;
};
</source>

==CMakeLists.txt==
<source lang="cmake">
cmake_minimum_required(VERSION 2.6)

Project(CustomIterator)

ADD_EXECUTABLE(CustomIterator CustomIterator.cpp)
</source>

CPP/CustomIterator - Revision history

Daviddoria: Created page with 'This example demonstrates what you have to implement to create an STL iterator. ==CustomIterator.cpp== #include template struct Poin…'