Is it compulsory to use "using namespace std" in new version !??

Question

I tried " Try yourself" in which it give an error , but where as it does not give any error in turbo C .

Answer 1

It is not compulsory to do "using namespace std". It never has been.

Just do:

std::cout
std::endl
etc

for objects which require it, if you are not declaring the use of std namespace for the program.

Answer 2

It's true that turbo c++ and many of older compiler don't give error messages when using namespace STD is not included.
But the new compilers and all the online compilers will give error if you exclude the statement.

Answer 3

What is the error that you are getting?
Also in which "try yourself" did you check?