hi i am starting with c++ and i have a question

in my book it says that c++ compilers made before of the standartization does not use the "using namespace std;" and that in the begginin of the file they put the extension of the #include like this: include <"iostream.h"> but that now it isnt need anymore...i have visual c++ 6.0 but it seems like an old compiler..anyone could explain me this?