dynamic method dispatch

how can we implement the run time polymorphisem,can any one expalian with example

Run-time polymorphism (also known as dynamic binding) allows a single object
name to refer to any member of an inheritance hierarchy and permits a procedure to
resolve at run-time which actual object is being referred to. This is useful because it
allows one to write programs in terms of a single type which would behave differently
depending on the actual type. Object-oriented languages support this behavior.
Fortran95 does not, with the exception of elemental functions.

thanq for u r reply,can u give me an example on the dynamic method dispatch.