Reset properties of std::cout for integers or doubles in C++

Question

At various places in my code, I set certain stream properties, such as in std::cout << fixed << 4.56342;, in order to manipulate how an integer or double appears when printed to standard out. Sometimes during a particular runtime flow, std::cout is used without any manipulations but the output is inadvertently transformed because of a preceding manipulation.

So, what is the best way to reset all such properties of std::cout so that a call to std::cout<< will behave precisely as in the following example:

#include <iostream>

int main(int argc, char **argv) {
    // let X be an integer or a double
    std::cout << X;
    return 0;
}

---

I see Effective use of C++ iomanip library, and it makes sense generally to not use the manipulators directly. That will be a good strategy going forward. Still, it would be nice to know how to undo all such manipulations as I describe above.

Answer 1

Use resetiosflags:

std::cout << std::resetiosflags( std::ios_base::basefield ); // clears integer manipulations
std::cout << std::resetiosflags( std::ios_base::floatfield  ); // clears floating-point manipulations
std::cout << std::resetiosflags( std::cout.flags() ); // clears all flags