ECS 36C Winter cs60
Programs must be written in C++ and are to be submitted using handin on
the CSIF by the due date (see Canvas) using the command:
handin cs60 Program1 file1 file2 ... fileN
Your programs must compile and run on the CSIF. Use handin to submit all
files that are required to compile (even if they come from the prompt). Programs
that do not compile with make on the CSIF will lose points and possibly
get a 0. Programs that have warnings during compilation will lose 10 out of 100
points.
An autograder along with examples and solutions will be available shortly.
1 Overview & Learning Objectives
In this program you will implement an AVL tree. There are multiple objectives
of this assignment:
1. strengthen your knowledge of JSON,
2. strengthen your understanding of code testing,
3. understand and implement an AVL Tree.
2 AVL Trees
Create a source file AVL.cpp and a header file AVL.h and implement an AVL
Tree as a C++ class called AVLTree. A binary search tree is implemented in
BST.cpp and BST.h using C++11 smart pointers weak_ptr and shared_ptr,
which are built to help you manage memory. For a tutorial on smart pointers,
see:
https://www.codeproject.com/Articles/541067/Cplusplus-Smart-Pointers
Briefly, abide by the following rules to use smart pointers for your AVL tree:
If v is a parent of u, then u has a std::weak_ptr that points to v.
1
Program 4
Due: 3/17/2019
ECS 36C Winter 2019
If w is a child of u, then u has a std::shared_ptr that points to w.
Use std::shared_ptr to modify what is being pointed to. In order to do
this for a parent, you must convert a std::weak_ptr to a std::shared_ptr
using lock.
To check for an empty smart pointer, compare a std::shared_ptr to
nullptr.
A std::weak_ptr may not be assigned nullptr; instead, use reset to
have a std::weak_ptr "point to null".
Implement the following.
ceptable.
As usual, input will be in the form of a JSON file, and output should be
printed to the screen. You can use CreateData.exe to generate input. Calling
./CreateData.exe 5 on the command line results in a file like this:
{
"1": {
"key": 2109242329,
"operation": "Insert"
},
"2": {
"key": -948648564,
"operation": "Insert"
},
"3": {
"key": -948648564,
"operation": "Delete"
},
"4": {
"operation": "DeleteMin"
2
AVL Insertion: that utilizes the rotations as described
at GeeksForGeeks:
https://www.geeksforgeeks.org/?p=17679
},
"5": {
"key": -289891961,
"operation": "Insert"
},
"metadata": {
"numOps": 5
}
}
Which results in a tree with one node with key -289891961. Your program will
read in input file such as the above, perform the operations in order, and print
a JSON object to the screen (stdout) with the following format:
A height key (JSON key) whose value is the tree’s height,
A root key (JSON key) whose value is the root’s key (AVL tree key),
A size key whose value is the number of nodes in the tree, and
For each node, a key/value pair where the JSON key is the node’s key and
the fields are:
height the height of the node,
balance factor the balance factor of the node, (use the right-left formula
for this)
parent the key of the parent node, if it exists
left the key of the left child node, if it exists
right the key of the right child node, if it exists
root the value of true, if the node is the root, otherwise do not include
this key.
For example, the tree given by:
3
1 5
100
Is encoded by the JSON object:
3
{
"1": {
"balance factor": 0,
"height": 0,
"parent": 3
},
"100": {
"balance factor": 0,
"height": 0,
"parent": 5
},
"3": {
"balance factor": 1,
"height": 2,
"left": 1,
"right": 5,
"root": true,
},
"5": {
"balance factor": 1,
"height": 1,
"parent": 3,
"right": 100
},
"height": 2,
"root": 3,
"size": 4
}
3 AVLCommands
Write a C++ program AVLCommands.cxx that does the following:
1. takes an input JSON filename representing a sequence of AVL tree operations
(Insert, Delete, and DeleteMin) as its first command-line argument,
2. creates an AVL tree using the operations described in the input JSON file,
3. prints the resulting AVL tree JSON object to the screen (stdout).
Name your executable AVLCommands.exe and add lines to your Makefile to
compile AVL.o and AVLCommands.exe.
4
4 Compilation
A Makefile has been provided for you. When you add new files to your program,
you will need to edit this Makefile.
5 Testing your code
In addition to the autograder, you may do the following to test your code.
Modify BSTSanityCheck.cxx for use with your AVL tree. The code does the
following:
lines 29-39: Creates a sequence of operations to test, including Inserts, Deletes,
and DeleteMins.
lines 40-44: Removes elements in sorted order from the tree, then compares
the result to a sorted array.
In addition, you should incorporate the following facts:
1. The balance factor of every node should be between -1, 0, and 1.
2. The height of every node should be 0 for leaves, 1 + child height if a node
has a single child, and 1 + the minimum of the children’s height if a node
has two children.
3. It turns out that for a tree of n nodes, an AVL tree has height less than
2 log n.
6 Files to turn in
1. AVL.cpp
2. AVL.h
3. AVLCommands.cxx
4. Makefile
5. BST.cpp (even if you have not modified it)
6. BST.h (even if you have not modified it)
7. CreateData.cxx (even if you have not modified it)