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#ifndef NUMERICRANGE_H
#define NUMERICRANGE_H
#include <iterator>
#include <stdexcept>
/*
* A (low memory usage) generator of ranges in steps of 1.
*/
template<typename T>
class NumericRange
{
public:
class iterator
{
friend class NumericRange;
public:
typedef iterator self_type;
typedef T value_type;
typedef T& reference;
typedef T* pointer;
typedef std::bidirectional_iterator_tag iterator_category;
typedef int difference_type;
iterator(const T &first): m_value(first) {}
T operator *() const { return m_value; }
const iterator &operator ++() {
++m_value;
return *this;
}
iterator operator++(int) {
iterator copy(*this);
++m_value;
return copy;
}
const iterator &operator --() {
--m_value;
return *this;
}
iterator operator--(int) {
iterator copy(*this);
--m_value;
return copy;
}
bool operator ==(const iterator &other) const {
return m_value == other.m_value;
}
bool operator !=(const iterator &other) const {
return m_value != other.m_value;
}
private:
T m_value;
};
/*
* The range [first, last).
*/
NumericRange(const T &first, const T &last)
: m_begin(first)
, m_end(last)
{
if (first > last) {
throw std::logic_error("first > last");
}
}
typedef const iterator const_iterator;
iterator begin() const { return m_begin; }
iterator end() const { return m_end; }
const_iterator cbegin() const { return m_begin; }
const_iterator cend() const { return m_end; }
private:
iterator m_begin, m_end;
};
#endif // NUMERICRANGE_H
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