range.cpp

// Python-like simple range in C++14

#include <iostream>
#include <type_traits>

template <typename T>
class Range {
  private:
    T first, last, iter, step;

  public:
    Range(T first, T last, T step = 1)
        : first(first), last(last), iter(first), step(step) {}

    // Iterable functions
    const Range& begin() const noexcept { return *this; }
    const Range& end() const noexcept { return *this; }
    const Range& cbegin() const noexcept { return begin(); }
    const Range& cend() const noexcept { return end(); }

    // Iterator functions
    bool operator!=(const Range&) const noexcept { return iter < last; }
    Range& operator++() noexcept {
        iter += step;
        return *this;
    }
    Range operator++(int) noexcept {
        Range cpy{*this};
        this->operator++();
        return cpy;
    }
    T operator*() const noexcept { return iter; }
};

// Convenience function for automatic type deduction
template <typename T>
auto make_range(T fist, T last, T step = 1) {
    return Range<T>{fist, last, step};
}

int main() {
    for (auto i : make_range(10, 20, 2)) {
        std::cout << i << std::endl;
    }

    auto it = make_range(-0.5, 0.5, 0.1);
    std::cout << *(it++) << std::endl;
    std::cout << *(++it) << std::endl;
    std::cout << *it << std::endl;
}