#include <iostream>
#include <ranges>

int main()
{
    using namespace std::views;
    
    auto output = 
          iota(1)
        | filter([](int x){ return x%2 == 0; })
        | transform([](int x){ return 3*x; })
        | take(10);
		
    // no calculation is done up to here (lazy evaluation)
		
    for (auto e : output) std::cout << 	e << ' ';
}