Question

what is a constuctor and destructor? My book is not saying what they are, just that they are.

Answer 1

a constructor is typically where you would initialise your newly constructed object. for example, this is where you might open a connection to a database, or allocate some memory, etc.

a destructor is the opposite - it is where you would finalise the object just before it gets destroyed. for example, this is where you might close a connection to a database, or free some memory, etc.

Answer 2

adding to the aboe definition a constructor is not called by an object.
It is just called when an object is created.When an object is created some variables must be intialised .