What is polymorphism? What are its types? Explain any one with example.

Polymorphism (many forms) lets one name behave differently — one interface, multiple implementations. Consistent with SI-paper terminology.

Types:

1. Compile-time (overloading) — Same method, different parameters; choice at compile time.
2. Runtime (overriding) — Child redefines parent method; choice at runtime via dynamic dispatch.

Example — runtime overriding (Java):

class Staff { void pay(){ System.out.println("Basic"); } }
class Doctor extends Staff { void pay(){ System.out.println("Doctor+allowance"); } }
Staff s = new Doctor(); s.pay(); // prints Doctor+allowance

Same call pay() gives different result by object. Benefit: processBill() works for OPD, Lab and Pharmacy objects without rewriting caller — extensible hospital modules.