function that takes and detects conditions of stream

fdcs.cpp

#include <iostream> /// std::istream; std::cout; std::endl;

std::istream &states (std::istream &is,const int &i) {
    is >> const_cast<int&>(i);

    if (is.rdstate () == std::cin.eofbit)
        std::cout << "reached end of file " << std::endl;
    else if (is.rdstate () == std::cin.badbit)
        std::cout << "bad bit " << std::endl;
    else if (is.rdstate () == std::cin.failbit) {
        std::cout << "fail bit " << std::endl;
    }
    else if (is.rdstate () == std::cin.goodbit)
        std::cout << "good bit " << std::endl;

    return is;

}

int main ()
{
    auto return_state = states(std::cin, 1).rdstate();

    if (return_state == std::cin.goodbit)
        std::cout << "return goodbit " << std::endl;
    else
        std::cout << "return badbit " << std::endl;

    return 0;
}