Isn't it #include <iostream.h>? Instead of #include <iostream>

Answer 1

Depends on the compiler.

#include is for linkage. Few compilers neglect file format. But it's the same file, so if you get errors while linking, just remove or add file format.

Answer 2

Actually, it used before 2002. But after 2002 c++ community and bell lab change it and remove .h from header file. From there this is the standard of c++. When you write iostream it simply means you are calling a header file. Now all compiler shows this as a standard of c++.

Answer 3

if the header file if of c the we use .h and if it's introduced in c++ then no need of use .h