python2 range in C++

python2-range.cpp

#include <iostream>
#include <vector>

template<class T> class vector;
template<class T> std::ostream& operator<<(std::ostream&, const vector<T>&);

template<class T> class vector : virtual public std::vector<T> {
public:
	friend std::ostream& operator<< <T> (std::ostream &out, const vector<T> &v);
};

template<class T>
std::ostream& operator<< (std::ostream &out, const vector<T> &v) {
	if (v.size() == 0) {
		out << "[]";
	} else if (v.size() == 1) {
		out << "[" << v.front() << "]";
	} else {
		out << "[" << v.front();
		for (auto i = v.begin() + 1; i != v.end(); ++i)
			out << ", " << *i;
		out << "]";
	}
	return out;
}

vector<int> range(int start, int end, int step) {
	vector<int> v;
	if (step > 0) {
		for (int i = start; i < end; i += step) v.push_back(i);
	}
	if (step < 0) {
		for (int i = start; i > end; i += step) v.push_back(i);
	}
	return v;
}

vector<int> range(int start, int end) { return range(start, end, 1); }
vector<int> range(int end) { return range(0, end, 1); }

int main() {
	std::cout << "range(5, 10) = " << range(5, 10) << std::endl;
	std::cout << "range(0, 10, 3) = " << range(0, 10, 3) << std::endl;
	std::cout << "range(-10, -100, -30) = " << range(-10, -100, -30) << std::endl;
	return 0;
}