Header file confusion

Question

which header file we must use after iostream.h
using namespace std or #include<conio.h>
i have confusion because in this app( using namespace std )is used. in my book (conio.h ) is used please clear my doubt

Answer 1

using namespace std isn't a header. Its a directive to make the compiler understand that the standard functions and classes we use in our code belong to the standard namespace (std) only and are not to be assumed as some overloaded versions.

The header conio.h, iostream.h and other headers with a '.h' are now deprecated as C++ was standardised in 1996, and the extensions were removed. You should not use these as compilers that still support these have not been updated since 1996, and the language has undergone various changes since then.

For more information, kindly visit:

https://www.sololearn.com/discuss/882544/?ref=app
https://www.sololearn.com/discuss/979840/?ref=app
https://www.sololearn.com/Discuss/1034591/?ref=app
https://www.sololearn.com/Discuss/1057364/?ref=app
https://www.sololearn.com/Discuss/1078987/?ref=app
https://www.sololearn.com/Discuss/1108354/?ref=app
https://www.sololearn.com/Discuss/232791/?ref=app

And yes, please don't use such books that are still not up to date with the language.