the arrow '->' separator is crashing when calling function from class

Question

I\'m working on a project for class and I\'m using classes and pointers of type class to call some functions in the class but it\'s crashing on Code Blocks and Eclipse and I don

Answer 1

Basic rule: creating a pointer (a variable that contains the address of an object, or otherwise is NULL (or nullptr since 2011)) as pointed out by Christian Hackl in comments) does not create a corresponding pointee (an object who's address can be stored in the pointer).

More formally, Ptr is an uninitialised pointer. Even accessing its value gives undefined behaviour (e.g. some_other_pointer = Ptr). For operator -> to work correctly, the pointer must first be initialised so it points at a valid object.

 a aobj;
 a *Ptr = &aobj;
 Ptr->set_X(42);   // OK

 a *Ptr2 = new a;
 Ptr2->set_X(42);    // OK
 delete Ptr2;