ReverseAdapter

C++ adapter for traversing a container in a range-for in reverse order (C++17).

#include "reversed.h"
#include <iostream>
int main(){
	using ::adapter::reversed;
	for(auto const &i : reversed({0,1,2,3,4,5})) {
        std::cout << i << '\n';
    }
}

will output

5
4
3
2
1
0

The C++17 deduction guides ensure that temporaries will be kept around in the reverse object and not dangle. Non-temporaries will be kept by reference without overhead.

I know that C++20 ranges will provide a std::reverse range adapter that will provide almost the same, except that you must ensure lifetimes yourself. For example, by using the initializer in the range for.

If there is interest, I might implement a similar solution with a factory function for C++11 as well. Please ask.