+ 2
Iāll try to explain this as best I can: Class hierarchy is like a family tree, in a way. Thereās the oldest (referred to as the āparentā in programming) and younger ones (referred to as the āchildā). If you need more, think of it like fish. Thereās the biggest fish eating smaller fish (a parent over the child). You can read a better explanation here:
http://www.modernescpp.com/index.php/c-core-guidelines-class-hierarchies
Hereās a diagram too, to help:
https://www.programtopia.net/sites/default/files/heirar_1.png