An Example of Good Documentation Style

CSCI 151 – section 04

PROGRAM: AVL TREE

AVLTREE.H

// AVLTree.h: interface for the AVLTree class.

//////////////////////////////////////////////////////////////////////

/****************************************************************

* Name: XXXXXXXXXXXXXXXXXXX

* Class Computer Science 151

* Assignment: Program 2

****************************************************************

Program 2: AVLTrees

Status Of Program: Completed

main() Complete and Tested

Usage() Complete and Tested

Class AVLTree Complete and Tested

AddKeyItem() Complete

AVLTree() Complete

~AVLTree() Complete

BalanceStack() Complete

DebugCheckTree() Complete

DebugVerifyTree() Complete

DeleteKeyItem() Complete

DeleteTree() Complete

FindImmediatePredecessor() Complete

FindImmediateSuccessor() Complete

GetStatusMessage() Complete

InOrderTraversal() Complete

LocateInsertDeletePosition() Complete

NodeBalanceFactor() Complete

NodeHeight() Complete

PostOrderTraversal() Complete

PreOrderTraversal() Complete

PrintNode() Complete

PrintNodeData() Complete

Rebalance() Complete

Rotate() Complete

SetFileOut() Complete

traverse_AVL_Inorder() Complete

traverse_AVL_PostOrder() Complete

traverse_AVL_PreOrder() Complete

UnwindAVLStack() Complete

UnwindQueues() Complete

Program Overview:

Functional Description:

This program generates an AVL tree, then reads commands from an input file,

processes those commands and sends the results to the specified output file.

See the "Commands and Formats" table in the specifications document.

Operational Description:

The program reads lines from a file specified in the program command line. Each command line is parsed and the commands are selected using the characters specified in the commands and formats table. Several commands (Add, Delete and Search) have additional fields containing a required integer. Results are sent to an output file, also specified in the command line.

The command line is AVLTrees CmdFile OutputFile [DEBUG].

CmdFile is the input file with commands.

OutputFile is the results file.

The DEBUG command line option changes the output format and causes the

AVLTree::DebugVerifyTree() function to be called after every node addition

or deletion to check the viability of the code.

****************************************************************************

Classes

******************************************************************************

AVLTree

Purpose: The AVL tree is maintained in an AVLTree class.

This class generates the tree and controls all access, additions and deletions.The AVLTree class utilizes a stack and several queues to track movement within the tree.

Functions: See the Specifications and Status Document.

******************************************************************************

Other Objects:

******************************************************************************

I_Node

Purpose: Structure defining a the node data to be stored in the AVL

tree.

******************************************************************************

Other Functions:

Usage()

Purpose: Displays the instructions to run this program.

TrimLine()

Purpose: Trim the command line (remove spaces from the front and

back).

******************************************************************************

Note:

All functions are original code except for AVLTree::traverse_AVL_Inorder(),AVLTree::traverse_AVL_PostOrder() and AVLTree::traverse_AVL_PreOrder() which were copied from the examples in the workbook and modified to format the output.

#if !defined(AFX_AVLTREE_H__275508E6_2E7B_11D4_805C_080009B93EFF__INCLUDED_)

#define AFX_AVLTREE_H__275508E6_2E7B_11D4_805C_080009B93EFF__INCLUDED_

#if _MSC_VER > 1000

#pragma once

#endif // _MSC_VER > 1000

#include <stack>

#include <queue>

#include "fstream.h"

//***************************************************************************

// AVLTree.h: header file for the AVLTree class. contains class declarations

// and information.

#define ROTATELEFT 100

#define ROTATERIGHT 101

//*************************************************************

// Structure: I_Node (integer node)

// Purpose: Used by the AVLTree class to hold integer data for the tree

// Archetecure

struct I_Node

{

int iValue; // KeyValue also data

I_Node *LeftChild; // Pointer to the LeftChildNode

I_Node *RightChild; // Ponter to the RightChildNode

int iHeight; // position in the tree from the bottom

// if this is a leaf node it will have a 0 height

// this is an absolute value

int iBalanceFactor; // Right child height - left child height

I_Node() // Constructor for I_Node

{

LeftChild=NULL;

RightChild=NULL;

iHeight=0;

iBalanceFactor=0;

} // constructor

};

//*************************************************************

// Class: AVLTree

// Purpose: Implement an AVL Tree with an integer key and provide the

//appropriate access to the tree.

// Implementation Note: We want to convert this to a template in the future.

class AVLTree

{

public:

AVLTree(); //Constructor: initializes Class variables

virtual ~AVLTree(); //Destructor: Deallocates any memory allocated

void SetFileOut(ofstream *ofile); // Set the target file

char * GetStatusMessage(); // Results of previous operation

I_Node * AddKeyItem(int ivalue); // Add a node to the tree

bool DeleteKeyItem(int iValue); // Remove a node from the tree

I_Node * FindValue(int iSearchKey); // Search for the key in the tree

// Traversals

void PostOrderTraversal(ofstream *ofile);

void PreOrderTraversal(ofstream *ofile);

void InOrderTraversal(ofstream *ofile);

private: //Functions

void BalanceStack();

int DebugCheckTree(I_Node *itree_ptr);

void DebugVerifyTree();

void DeleteTree(I_Node *rootptr);

int FindImmediateSuccessor(I_Node *inode);

int FindImmediatePredecessor(I_Node *inode);

I_Node * LocateInsertDeletePosition(int iValue);

int NodeBalanceFactor(I_Node *inode);

int NodeHeight(I_Node *inode);

void PrintNode(I_Node *inode);

void PrintNodeData(I_Node *inode, bool bPrintTitle=false);

void Rebalance(I_Node *UnBalancedNode, I_Node *ParentOfUnBalancedNode);

void Rotate(int iRotateType,I_Node *PivotNode, I_Node *ParentNode);

void traverse_AVL_PostOrder(I_Node *itreeptr);

void traverse_AVL_PreOrder(I_Node *treeptr);

void traverse_AVL_Inorder(I_Node *itree_ptr);

void UnwindAVLStack();

void UnwindQueues();

private: //Data

I_Node * Root; // Pointer to the root node

int iNodeCount; // Number of Nodes in the tree

char StatusString[100]; // What happened in the last operation

bool bError; // Some type of error in the last operation

bool bFound; // Search string was found

ofstream * OutFile; // Output File Stream

// We must specify the std name space here

// because stack is a Standard Library template

std::stack<I_Node *> AVLStack; // Declare the stack

std::queue<I_Node *> PredecessorQueue;

std::queue<I_Node *> SuccessorQueue;

};

#endif // !defined(AFX_AVLTREE_H__275508E6_2E7B_11D4_805C_080009B93EFF__INCLUDED_)

AVLTREE.CPP

// AVLTree.cpp: implementation of the AVLTree class.

//////////////////////////////////////////////////////////////////////

#include "stdafx.h"

#include "iomanip.h"

#include "AVLTree.h"

extern bool gDebug; //global definition

//////////////////////////////////////////////////////////////////////

// Construction/Destruction

//////////////////////////////////////////////////////////////////////

AVLTree::AVLTree()

{

// FUNCTION: AVLTree() //Constructor

// Preconditions: None

// PostConditions: an empty AVL tree is created

// Global vars: none

// Local vars: None

// Class vars: iNodeCount, Root

// Function Calls: None

// Functional Desc: Constructor; Initialize Class variables

// Operational Desc: Set class variables to their intial condition

iNodeCount=0; // There are no nodes in the tree

Root = NULL; // There is no root node

strcpy(StatusString,"AVLTree Initialized");

}

//*********************************************************

AVLTree::~AVLTree()

{

// FUNCTION: ~AVLTree() //Destructor

// Preconditions: The class existed, is now being deleted

// PostConditions: The tree is deleted, all memory is freed

// Global vars: none

// Local vars: None

// Function Calls: DeleteTree()

// UnwindQueues()

// UnwindAVLStack()

// Functional Desc: Deletes the AVL tree and all memory allocated

// in this calls

// Operational Desc: Calls DeleteTree() to delete all nodes in the tree.

// UnwindAVLStack and UnwindQueues

// to ensure that

// these objects are ready for deletion.

UnwindQueues(); // Clear the Queue Memory

UnwindAVLStack(); // Clear the stack memory

DeleteTree(Root); // Clear the tree

} //AVLTree::~AVLTree()

//*********************************************************

I_Node * AVLTree::FindValue(int iSearchKey)

{

// FUNCTION: I_Node * FindValue(int iSearchKey)

// Preconditions: iSearchKey contains the integer value to search on

// PostConditions: Returns a pointer to the node with the matching // value

// Global vars: none

// Class vars: Root

// Local vars: I_Node *inode

// Function Calls:sprintf(), strcpy()

// Functional Desc: Search the tree for a specific value

// Operational Desc: Check for a NULL root, indicating an empty tree

// At each node check for a match, then select the

// direction of the next node based on less than

// or greater than values.

// Handle an empty tree

if (Root == NULL) //empty tree;

{

strcpy(StatusString, "Empty Tree");

return(NULL);

}

I_Node *inode=Root; // set our temp variable to the root node to start

// check for a match at every node that we traverse.

while(inode !=NULL)

{

// Check for a match

if (iSearchKey == inode->iValue) //Is this a match

{

sprintf(StatusString,"Node Found: Value = %d ",inode->iValue);

//Set status

return(inode);

}// if (iSearchKey == inode->iValue)

// Check for greater than

if (iSearchKey > inode->iValue) // Go down the right hand path

{

if (inode ->RightChild == NULL)

{

strcpy(StatusString, "Node Not Found");

return(NULL);

}//if (inode ->RightChild == NULL)

inode=inode->RightChild; // getthe next node in the path

}//if (iSearchKey > inode->iValue)

else // less than

{ //

if (inode->LeftChild== NULL) // Node does not exist

{

strcpy(StatusString, "Node Not Found");

return(NULL);

}//if (inode->LeftChild== NULL)

inode=inode->LeftChild; // Get the next node in the path

}//if (iSearchKey > inode->iValue)

}// while(inode !=NULL)

// if we get to here it is an error

strcpy(StatusString,"Error: FindValue : Processing Error");

return(NULL);

}//I_Node * AVLTree::FindValue(int iSearchKey)

//*********************************************************

etc………………………………………….

AVLTREES.CPP

// AVLTrees.cpp : Defines the entry point for the console application.

#include "stdafx.h"

#include "iostream.h" // Needed for cout

#include "fstream.h" // Needed for ifstream, ofstream

#include "string.h" // Needed for strlen

#include "stdlib.h" // Needed for atoi

#include "AVLTree.h" // AVLClass definition

// define non class functions called by main

void Usage(); // display the user commands

void TrimLine(char *iLine); // Trim whitespace from a line

// Definitions for main and non class functions

#define MAXLINESIZE 100

// Global Definitions

bool gDebug=false;

//****************************************************************************

int main(int argc, char* argv[])

{

// FUNCTION: int main(int argc, char *argv[])

// Preconditions: Command line must contain the source file and the

// target file

// PostConditions: none

// Global vars: none

// Local vars: XXX

// Function Calls:

// Functional Desc: Verify the command line, open the files,

// parse the source file's commands, execute the commands by

// calling appropriate functions.

// Operational Desc: main() first checks the command line to ensure both

// a source file and a target file have been specified.

// Then the source file and target file are opened, (if either is

// unable to be opened main() displays a message and exits).

// Each line of the source file is read and parsed. A switch

// statement controls the selection of the routines to execute

// for each of the commands.

// Both files are closed implicitly at program exit.

// Verify the command line

if ((argc != 3)&& (argc !=4)) //There must be three command line

// arguments (Program, SourceFile, TargetFile)

{

Usage(); // Display the instruction

return(1); // Exit the program

}

if (argc == 4)

{

if (strcmp("DEBUG",argv[3]) ==0)

gDebug=true;

}

// Instantiate the AVL Tree

AVLTree AVL;

// open the source file

// input mode (default)

// no create mode (To check for the files existance and not

// create it

// text mode (default)

ifstream SourceFile(argv[1], ios::nocreate);

// Verify the file is opened

if (SourceFile.fail() )

{

Usage();

cout << "***************************************" << endl;

cout << "Unable to open the InputFile: " << argv[1] << endl;

cout << "***************************************" << endl << endl;

return(1); // exit the program

}

// open the target file

ofstream TargetFile(argv[2]); // Create the outputfile instantiation

// open the output file

// Will close when the ofstream class

// destructor gets automatically called at the

// termination of the program

// Verify the file is opened

// display error message if the file does not exist

// (or cannot be written to)

if(TargetFile.fail())

{

Usage();

cout << "***************************************" << endl;

cout << "Unable to open the OutputFile: " << argv[2] << endl;

cout << "***************************************" << endl << endl;

return(1); // exit the program

}

AVL.SetFileOut(&TargetFile);

// Set up the loop conditions

char LineBuffer[MAXLINESIZE];

int iKeyValue;

bool bKeyRead; // The keyvalue has been read out of the line

// Start the loop

while( !SourceFile.eof())

{

// Read each line of the Source file

SourceFile.getline(LineBuffer,sizeof(LineBuffer));

// clear the white space before and after the line

// to ensure we don't have any translation problems

TrimLine(LineBuffer);

cout << LineBuffer << endl;

// Parse each line of the Source file

bKeyRead=(strlen(LineBuffer) >= 3);

// There is a keyvalue on this line

if (bKeyRead)

iKeyValue = atoi(&LineBuffer[2]);

// Save the line in the output file

TargetFile << LineBuffer << endl;

// Execute the parsed commands in the source file

switch (LineBuffer[0])

{

case 'A': //Add the integer to the AVL Tree;

if (!bKeyRead) // Ensure there was a keyvalue

TargetFile << "Error: No KeyValue Read" << endl;

AVL.AddKeyItem(iKeyValue);