with C++ you can do everything you are the programmer master of the universe.. also good for system and hardware near programming but at least you should learn one more like C# if it goes more to user interfaces then normal c++ is a pain in the butt
c is old but good for hardware programming the evolution is so C => C++ => C#
Java is good if you want to develop apps for mobile devices.. but it lacks if you want to go deeper into BS
but Java and the C family tree has some similarities in language someone who knows c++ will easily learn java there are some really big differences but once you learn one language you can learn another too..
Delphi works on mac windows and mobile devices the problem is that it is not so wide spread like C or java a good programming language for user interfaces, Internet, DB etc.. eg if you want to programm a file commander or a email program than I would prefer Delphi
do not learn Visual Basic
a good thing also would be learn a real Language stick to OOP and than a script language..