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Forked from jeetsukumaran/custom_iterator.cpp
Created November 17, 2020 01:05
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Sample C++/STL custom iterator
// Sample custom iterator.
// By perfectly.insane (http://www.dreamincode.net/forums/index.php?showuser=76558)
// From: http://www.dreamincode.net/forums/index.php?showtopic=58468
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
#include <cassert>
template <typename T>
class fixed_array
{
public:
typedef int size_type;
class iterator
{
public:
typedef iterator self_type;
typedef T value_type;
typedef T& reference;
typedef T* pointer;
typedef std::forward_iterator_tag iterator_category;
typedef int difference_type;
iterator(pointer ptr) : ptr_(ptr) { }
self_type operator++() { self_type i = *this; ptr_++; return i; }
self_type operator++(int junk) { ptr_++; return *this; }
reference operator*() { return *ptr_; }
pointer operator->() { return ptr_; }
bool operator==(const self_type& rhs) { return ptr_ == rhs.ptr_; }
bool operator!=(const self_type& rhs) { return ptr_ != rhs.ptr_; }
private:
pointer ptr_;
};
class const_iterator
{
public:
typedef const_iterator self_type;
typedef T value_type;
typedef T& reference;
typedef T* pointer;
typedef int difference_type;
typedef std::forward_iterator_tag iterator_category;
const_iterator(pointer ptr) : ptr_(ptr) { }
self_type operator++() { self_type i = *this; ptr_++; return i; }
self_type operator++(int junk) { ptr_++; return *this; }
const reference operator*() { return *ptr_; }
const pointer operator->() { return ptr_; }
bool operator==(const self_type& rhs) { return ptr_ == rhs.ptr_; }
bool operator!=(const self_type& rhs) { return ptr_ != rhs.ptr_; }
private:
pointer ptr_;
};
fixed_array(size_type size) : size_(size) {
data_ = new T[size_];
}
size_type size() const { return size_; }
T& operator[](size_type index)
{
assert(index < size_);
return data_[index];
}
const T& operator[](size_type index) const
{
assert(index < size_);
return data_[index];
}
iterator begin()
{
return iterator(data_);
}
iterator end()
{
return iterator(data_ + size_);
}
const_iterator begin() const
{
return const_iterator(data_);
}
const_iterator end() const
{
return const_iterator(data_ + size_);
}
private:
T* data_;
size_type size_;
};
int main()
{
fixed_array<double> point3d(3);
point3d[0] = 2.3;
point3d[1] = 3.2;
point3d[2] = 4.2;
for(fixed_array<double>::iterator i = point3d.begin(); i != point3d.end(); i++)
{
std::cout << *i << " ";
}
std::cout << std::endl;
std::vector<double> vec;
std::copy(point3d.begin(), point3d.end(), std::back_inserter(vec));
for(std::vector<double>::iterator i = vec.begin(); i != vec.end(); i++)
{
std::cout << *i << " ";
}
std::cout << std::endl;
return 0;
}
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