How to resolve “pure virtual method called”

By the time your destructor is called, the destructor of inherited classes has already been called. Within constructors and destructors, the dynamic type of the object can effectively be considered to be the same as the static type. That is, when you call virtual methods from within your constructors/destructors it’s not the overriden versions of … Read more

What can cause a pure virtual function call in C++?

“The most common error I’ve seen that causes this is calling a virtual function from a base class constructor or destructor.” When an object is constructed, the pointer to the virtual dispatch table is initially aimed at the highest superclass, and it’s only updated as the intermediate classes complete construction. So, you can accidentally call … Read more

Undefined symbols “vtable for …” and “typeinfo for…”?

If Obstacle is an abstract base class, then make sure you declare all its virtual methods “pure virtual”: virtual void Method() = 0; The = 0 tells the compiler that this method must be overridden by a derived class, and might not have its own implementation. If the class contains any non-pure virtual functions, then … Read more

Pure virtual methods in C#?

My guess is that whoever told you to write a “pure virtual” method was a C++ programmer rather than a C# programmer… but the equivalent is an abstract method: public abstract void TurnRight(); That forces concrete subclasses to override TurnRight with a real implementation.