[solved] how to call a class from my own library, inside another own library

Using Arduino Programming Questions
8

Cpu.cpp does not include Cpu.h, this may cause problems.

CpuOutput outputObject;

It should be in the cpp or declared extern, if you want it in the header, the compiler may also need CpuOutput.h to be included in the header.

CpuOutput outputObject();

This is incorrect as it is a function prototype, taking no parameters and returning a CpuOutput object.