Verified answer

yes, everything in an interface must be implemented. The difference is that an interface is strictly only method declarations while abstract class allows actual method code (as well as declarations)

the different subject to undergo in ideas is maximum OO languages can inherit yet a single type, yet enforce many Interfaces. So, the clarification to apply a organic precis type may well be if the issue you're inheriting "particularly is a" member of the precis type. in any different case, enforce it as an interface...