@Thomas1965 - Yes, conio.h is specific to Windows, but it does not come with Windows.
conio.h came with Turbo C/C++, which is antiquated and not standards compliant.
conio.h should NOT be used when writing standards compliant C++ programs.
yes you are right, it does not come with Windows but with the Windows SDK, but also with MinGW, GCC, Borland C++Builder and probably some other compilers as well.