you got 2 choices. or you comment the "using namespace std" line and use std:: in front of all the types that need it OR you uncomment the line and remove std:: in front of all the types that need it.
A namespace is a realm in which the code is defined.
you can define some code in a namespace like this
namespace blah {
typedef bloh int;
}
blah::bloh myvar = 4;
if I insert this
use namespace blah;
then I can only use
bloh myvar = 4;
