Error: main.cpp: warning: using directive refers to implicitly-defined namespace ‘std’
If you see the following error when trying to compile a C++ application:
main.cpp: : : warning: using directive refers to implicitly-defined namespace 'std'then that means you do not have any header file inclusion that uses std namespace.
You can fix this warning by including a C++ header file that uses a std namespace otherwise the compile will not know about std namespace.
How to Solve this Error:
Very simple, just include a c++ header file, as follows:
#include <iostream>