Std is not a class or namespace

edit:**SOLVED** 'std' is not a class or namespace name ?????
I'm getting the error "'std' isnotaclassornamespacename" Can you find the error in this piece of code?? I guess stdis defined as a namespace in some .h somewhere, but I've tried about everyone I could think of (stdio, stddef, stdlib, etc) with no success. #ifndef MYCLASS #define MYCLASS.

error C2653: 'std' : is not a class or namespace... -
It won''t recognise stdclass, and I tried adding using namespacestd at the top but still doesn''t recognise it. I usually use just cout without the std and that works fine I only just decided to try std::cout and I have no idea what''s wrong, I added iostream and did exactly what the book said:S.

Qstring is not a class or namespace name - Qt Forum
Trying to create a program, when I build it at the end, it says the following error message: "Qstring isnotaclassornamespacename" and also "number identifier not found". Any help or suggestions?