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Python ranges in C++
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#ifndef RANGE_HPP_ | |
#define RANGE_HPP_ | |
template<typename T> class RangeIterator; | |
template<typename T> | |
class Range | |
{ | |
T _start, _end, _step; | |
public: | |
Range(T start, T end, T step = T(1)) | |
: _start(start), _end(end), _step(step) | |
{ | |
} | |
RangeIterator<T> begin() const; | |
RangeIterator<T> end() const; | |
}; | |
template<typename T> | |
Range<T> range(T end) | |
{ | |
return Range<T>(T(0), end, T(1)); | |
} | |
template<typename T> | |
Range<T> range(T start, T end, T step = T(1)) | |
{ | |
return Range<T>(start, end, step); | |
} | |
template<typename T> | |
class RangeIterator | |
{ | |
T _pos, _step; | |
public: | |
RangeIterator(T pos, T step) : _pos(pos), _step(step) {} | |
bool operator!=(const RangeIterator &o) const { return _pos < o._pos; } | |
RangeIterator &operator++() { _pos += _step; return *this; } | |
RangeIterator operator++(int) { RangeIterator copy(*this); operator++(); return copy; } | |
T operator*() const { return _pos; } | |
}; | |
template<typename T> | |
RangeIterator<T> Range<T>::begin() const { return RangeIterator<T>(_start, _step); } | |
template<typename T> | |
RangeIterator<T> Range<T>::end() const { return RangeIterator<T>(_end, _step); } | |
#endif /* RANGE_HPP_ */ |
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Alternative approach to
RangeIterator::operator!=
which supports negative step sizes (or at least seems to ... don't bank your production on this just yet):bool operator!=(const RangeIterator &o) const { return (o._pos - _pos) * _step > T(0); }