programming style

hello all...I'm in the process of making a program for homework that will include multiple classes. I was wondering what is a good convention for writing the classes. Would it be better to either have all the classes in a single .h file, and then have a seperate .cpp implementation file for each class. Or to have a different .h file for each class...
how is it done in the industry? what is most practical,

thanks, axon

the way I do it, is using a separate .h file for each class.

ive always been told to put the class in its own header and define all of the non-inline functions in a .cpp with the same name as the header.

or you put the whole class in the header if its a class template.