C++17 STL Cookbook

How to do it...

We are going to implement a helper class that solves the problem of redirecting a stream and reverting that redirection again with constructor/destructor magic. And then we see how we can put it to use:

1. We only need the headers for input, output, and file streams this time. And we declare the std namespace as a default namespace for lookup:

      #include <iostream>      #include <fstream>           using namespace std;

2. We implement a class, which holds a file stream object and a pointer to a stream buffer. The cout as a stream object has an internal stream buffer, which we can simply exchange. And while we exchange it, we can save what it was before, so we can undo any change later. We could look its type up in the C++ reference, but we ...