CSE 12, Week Six, Lecture Two Discussion: Getting started on hw7 & hw8

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1 CSE 12, Week Six, Lecture Two Discussion: Getting started on hw7 & hw8 Tree: What: - A container object - Composed of a TNodes o Each TNode holds - One root TNode pointer o The TNode in the Tree - Zero or more left and right child TNodes o tree: = left and right o Each points down the Tree o Serve as the infrastructure of the Tree o Similar to pre and next of List - Optional parent pointer o Points the Tree - Search Tree: o Order implemented: Smaller items go left.

2 Tree terminology and properties: - : the TNode without a parent, o entry point into the Tree - : a TNode without a child - : TNodes that share the same parent - : a TNode in a search path that follows from an ancestor. - : a TNode in a search path that terminates with a descendent. - : o 1 + height of tallest child o 0 for a leaf - : o left-height right-height o -1 height of non-existent children. - : the TNodes visited from the root to a leaf followed when searching for an element. o does not visit all TNodes. - : visiting every TNode in the Tree o : visit, go left, go right o : go left, visit, go right o : go left, go right, visit - : the action to take when at a TNode. Spindly trees: Bushy trees:

3 # of TNodes in an optimally balanced Tree: all leaf TNodes at the same level # of TNodes to check for unsuccessful search or to perform insert in an optimally balanced Tree More on Tree : Use of a : - Use of an : - Use of a : -.

4 Removing from Tree: - Real remove is a challenge o delayed until hw8 - remove o removal algorithm of hw7 o the item is not there o lookup with return o writing Tree display item o item is really the structure of Tree o no changing of height, balance o flag will true or false.

5 Implementation Decisions: Tree class, TNode class Loop based solution of Insert (for example): Tree Insert method, TNode Insert method - current/working TNode to refer to TNode of - starts at - reassigned to of current as you go the Tree. - algorithm of hw7 - height and balance need to be updated as you go the Tree when performing an insert: o pointer is needed. Recursive solution for Insert: Tree Insert method, TNode Insert method - Tree method o operates at o delegates to for any further task - TNode method o operates at o delegate to for any further task - algorithm of hw8 - no is needed to go the Tree as you update height and balance.

6 Extending current access rights in spite of restrictive derivation: - What: Extend the current level of access regardless of the derivation. - How: List the parent fields with using keyword with scope resolution operator in the child class corresponding to the original access right section from the parent class. - Ex: using Tree<Whatever>::Insert; Scope resolution examples: int aaa; // global class SomeClass { int aaa; int somefunc (); }; int SomeClass::somefunc () {... } int aaa = SomeClass::aaa; aaa = this->aaa; aaa = ::aaa; // resolves to

7 class Parent { private: int aaa; protected: int bbb; public: int ccc; }; class Private : private Parent { private: int ddd; protected: int eee; public: int fff; }; class Protected : protected Parent { private: int ggg; protected: int hhh; public: int iii; }; class Public : public Parent { private: int jjj; protected: int kkk; public: int lll; }; int main () { Parent MomDad; // bytes Private Eye; // bytes Protected Wilderness; // bytes Public Property; // bytes // scope resolution main Parent:: Public:: MomDad.aaa = 10; MomDad.bbb = 10; MomDad.ccc = 10; Eye.aaa = 10; Eye.bbb = 10; Eye.ccc = 10; Eye.ddd = 10; Eye.eee = 10; Eye.fff = 10; Wilderness.aaa = 10;

8 Wilderness.bbb = 10; Wilderness.ccc = 10; Wilderness.ddd = 10; Wilderness.eee = 10; Wilderness.fff = 10; Wilderness.ggg = 10; Wilderness.hhh = 10; Wilderness.iii = 10 Property.aaa = 10; Property.bbb = 10; Property.ccc = 10; Property.jjj = 10; Property.kkk = 10; Property.lll = 10; aaa = 10; bbb = 10; ccc = 10; ddd = 10; eee = 10; fff = 10; ggg = 10; hhh = 10; iii = 10; jjj = 10; kkk = 10; lll = 10; }

9 Constructor rules: - Don t have a return type. - More than one can exist per class. o Distinguished by parameter list (overloading) - Called when an instance comes into existence: o RTS objects: : Local objects (default or overloaded constructor) Parameter objects ( constructor) Reference parameters are not new objects o constructors are called for reference parameters. Return result objects ( constructor) Reference results are not new objects o constructors are called for reference results. o Heap objects:. o Data objects:!

10 Default constructor: - Used to create an object without passing parameters to constructor. - Prototype syntax: Classname (void); - Sometimes the default constructor is optional: o If all instances are created by passing parameters to constructors. Default constructor is optional since it was never called. o If all instances are created without passing parameters to constructors. No constructors are ever called. Therefore, no constructors need to exist! Instantiated object was created not constructed. - Sometimes the default constructor is mandatory: o If instances are created both by passing parameters and without passing parameters to constructors. One you define the non-default constructor, you must define default one, too (as long as you are creating default objects).

11 Copy constructor: - Used to create an object from another object. - Prototype syntax: Classname (Classname &); - Implicitly called: o Creating an object as a parameter to a method. o Creating an object as a return result from a method. - Always optional: o Default behavior if missing: Member-wise copy is made. New object created is distinct from the original if the object is flat (no pointer data fields). Instantiated object was created not constructed.

12 Destructor rules: - Don t have a return type. - Only one can exist per class. o No parameters can be passed to it. - Used to destroy or clean up when an instance goes out of scope. - Prototype syntax: ~Classname (void); - Always optional: o Okay to not have one when the object is flat. o If pointer fields exist, then you ll need to deallocate memory with delete inside the body of destructor. Otherwise:. - Implicitly Called: o When a constructed object goes out of scope. RTS objects:. Heap objects:. Data objects:. - Can be explicitly called: o Code of destructor executed like any other method. Can be used to re-initialize an object. Rarely done. Destroying an array of heap objects: - Array brackets are needed to let the compiler know to call the destructor on all instances in the array. - Syntax: delete [] array_name;

Iterator: A way to sequentially access ( traverse ) each object in a container or collection. - Access is done as needed, not necessarily at once.

CSE 12, Week Seven, Lecture One Iterator: A way to sequentially access ( traverse ) each object in a container or collection - Access is done as needed, not necessarily at once. - Implemented by a private