Is it possible to pass derived classes by reference to a function taking base class as a parameter
Solution 1:
Yes. You don't have to upcast your objects. All references/pointers to derived types are converted implicitly to base objects references/pointers when necessary.
So:
IBase* ptr = new CFoo("abc"); // good
CFoo* ptr2 = static_cast<CFoo*>(ptr); // good
CFoo* ptr3 = ptr; // compile error
CFoo instance("abc");
IBase& ref = instance; // good
CFoo& ref2 = static_cast<CFoo&>(ref); // good
CFoo& ref3 = ref; // compile error
When you have to downcast you may want to consider using dynamic_cast, if your types are polymorphic.