1. Design Patterns

2. What is a Design Pattern? Generic pattern for solving a certain class of problem Learn to recognize the class of problem and apply a solution you already know A more structured/systematic way of thinking about program design

3. Common Patterns Functor Adapter Iterator Composite Observer

4. Functor A class with a single function and no data Often used to compare two objects Pass to a function objects to be compared and a functor object that can compare them Example: a different implementation of SortedList More generally: you may want to have a class that knows how to perform a function on given data, but does not store the data or results

5. Adapter/Wrapper Change or extend the interface of a class –May also wrap primitive types Example: miles to km

6. Iterator Goal: an interface that will allow the programmer to traverse through any collection Operations: bool hasNext() const Object & next() Example: iterate through SortedList of names

7. Iterator Example Code http://www.cs.fiu.edu/~weiss/adspc++2/code/Iterator1.cpp http://www.cs.fiu.edu/~weiss/adspc++2/code/Iterator3.cpp

8. Composite An object containing two other objects –Key, value pairs Idea: group together so that both can be returned from a function Example from Project 1?