I've been programming in Java and C# for a while and I guess I always thought of objects and classes as being one and the same but the C++ course I'm following has the classes in .h files and the objects .cpp files. Is this typically how a C++ program is structured? Is the class/object relationship different than other OOP's?
2 Answers
You might as well see classes declarations in a .cpp file, e.g., if the one who wrote this file decided to use some help-classes that weren't supposed to be part of the API presented in the .h file. Also, you might see in a .h file an object that is being held within a class as its private member.
Indeed, Java "pushes" you towards a pretty strict source and class files organization, that in many cases will match your folders & files organization. C++ allows you much more freedom in this regard, but however has the notion of includeing header files.
Comments
The relationship between the class and the object is not different to other languages. The object is an instance of the class.
So for example:
Car myCar("licence-plate123"); Car is the class. myCar is an instance of the Class Car and therefore the object.
To seperate the Class declaration is more like a convention and has nothing to do with objects and classes.
The .h-File contains the class description. There you can see, which methods the class provides, and what parameters they need. The .cpp-Files describe how each method works. So the actual source-code.
But as I have already said: This is more like a convention. You can also write all of it in the .h-File. It's not pretty but it works
3 Comments
BBDev
Ok so I guess what confused me is that a class's description, method's are all contained in a single .cs fie in c# but in c++ the object's properties and methods have to be described in the .h before implemented in the .cpp. Is this right?
Andreas
Yes that's right. Although, as mentioned, you do not have to
BBDev
Great! Thank you very much this really helped everyone.
int a;, class is to the object asintis to thea.