I read the section (8.21) as Dave mentioned from LRM.
It says…
A virtual method in an abstract class may be declared as a prototype without providing an implementation. This is called a pure virtual method and shall be indicated with the keyword pure together with not providing a method body. An extended subclass may provide an implementation by overriding the pure virtual method with a virtual method having a method body.
Does this mean pure virtual method can only exist in abstract class?