/in/call.cpp:5:37: error: use of multiple declarators in a single using declaration is a C++17 extension [-Werror,-Wc++17-extensions]
using std::cout, std::cin, std::endl;
                                    ^
1 error generated.
/in/Compile/Makefile:39: recipe for target 'buildCall' failed
make: *** [buildCall] Error 1