A Review of the OOP Polymorphism Concept. Textbook: T. Issariyakul and E.
Hossain, Introduction to Network Simulator NS2, Springer 2008. 1 ...
A Review of the OOP Polymorphism Concept
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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O li Outline • Overview • Type Casting and Function Ambiguity • Virtual Functions,, Pure Virtual Functions,, and Abstract Class • Non Type Casting Programming, and S l bilit P Scalability Problems bl • Class Composition Framework • Summary S mm
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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P l Polymorphism: hi Overview O i • A An iimportant t t conceptt iin object bj t oriented programming (OOP) • A polymorphic l hi f function ti
– acts differently under different context. context – has different implementation under different context.
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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P l Polymorphism: hi Inheritance I h i • Receptionist R ti i t and dh how th they greett customers t
– Friendly: “Good morning. How can I help you today?” – Moody: y “What do you y want?” – Rude: “What do you want? I’m busy. Come back later”
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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P l Polymorphism: hi Ex E 1
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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P l Polymorphism: hi Example E l
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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Polymorphism: Ex 2 • Modify class MoodyReceptionist
Why?: Receptionist says nothing.
INHERITANCE
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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O li Outline • Overview • Type Casting and Function Ambiguity • Virtual Functions,, Pure Virtual Functions,, and Abstract Class • Non Type Casting Programming, and S l bilit P Scalability Problems bl • Class Composition Framework • Summary S mm
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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Polymorphism: Ex 3 • Ex1:
• Three variables, variables Three classes • No type casting!
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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Polymorphism: Ex 3 • Based on Ex1: Let implement type casting main() { FriendlyReceptionist *f_pt; MoodyReceptionist *m m_pt, pt, *r r_pt; pt; f_pt = new FriendlyReceptionist(); m_pt = new MoodyReceptionist(); r_pt = new RudeReceptionist(); cout>./receptionist >> /receptionist ------------ Friendly Receptionist --------Say: Good morning. How can I help you today? ------------ Moody Receptionist i i Say: What do you want?
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------------ Rude Receptionist ------------Say: What do you want?
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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Vi Virtual l Functions: F i Ex4 E 4 • Ex E 3: 3 >>./receptionist ------------ Friendly Receptionist --------Say: Good d morning. i How can I h help l you today? d ------------ Moody Receptionist Say: What do you want?
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------------ Rude Receptionist ------------Say: What do you want?
Textbook: T. Issariyakul and E. Hossain, Introduction to Network Simulator NS2, Springer 2008.
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Vi Virtual l Functions: F i Ex4 E 4 • Based on Ex 3,, modify y class Receptionist p class Receptionist { public: virtual void greet() {coutgreet(); coutgreet(); cout
