COP4338 Assignment #1: Sorting with Binary Search Tree solution


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Through this programming assignment, the students will learn to do the following:

1. Know how to process command line arguments.
2. Perform basic file I/O.
3. Use structs, pointers, and strings.
4. Use dynamic memory.

This assignment asks you to sort the lines of an input file (or from standard input) and print the
sorted lines to an output file (or standard output). Your program, called bstsort (binary search tree
sort), will take the following command line arguments:

% bstsort [-c] [-o output_file_name] [input_file_name]

If -c is present, the program needs to compare the strings case sensitive; otherwise, it’s case
insensitive. If the output_file_name is given with the -o option, the program will output the sorted
lines to the given output file; otherwise, the output shall be the standard output.

Similarly, if the
input_file_name is given, the program will read from the input file; otherwise, the input will be from
the standard input. You must use getopt() to parse the command line arguments to determine the
cases. All strings will be no more than 100 characters long.

In addition to parsing and processing the command line arguments, your program needs to do the

1. You need to construct a binary search tree as you read from input. A binary search tree is a
binary tree. Each node can have at most two child nodes (one on the left and one on the right),
both or either one can be empty. If a child node exists, it’s the root of a binary search tree (we
call subtree).

Each node contains a key (in our case, it’s a string) and a count of how many of
that string were included. If he left subtree of a node exists, it contains only nodes with keys
less than the node’s key. If the right subtree of a node exists, it contains only nodes with keys greater
than the node’s key.

You can look up binary search tree on the web or in your Data Structure
textbook. Note that you do not need to balance the binary search tree (that is, you can ignore all
those rotation operations) in this assignment.

2. Initially the tree is empty (that is, the root is null). The program reads from the input file (or stdin)
one line at a time; If the line is not an empty line and the line is not already in the tree, it should
create a tree node that stores a pointer to the string and a count of 1 indicating this is the first
occurrence of that string, and then insert the tree node to the binary search tree.

An empty line
would indicate the end of input for stdin, an empty line or end of file would indicate the end of
input for an input file. If the line is not an empty line and the line is already in the tree, increase
the count for that node indicating that there are multiple instances of that line.

3. You must develop two string comparison functions, one for case sensitive and the other for case
insensitive. You must not use the strcmp() and strcasecmp() functions provided by the C library.
You must implement your own version. You will be comparing the ASCII values. Note that using
ASCII, all capital letters come before all lower case letters.

4. Once the program has read all the input (when EOF is returned or a blank line encountered), the
program then performs an in-order traversal of the binary search tree to print out all the strings
one line at a time to the output file or stdout.

Next to the line include a count of how many times
that line appeared. If the selection was for case insensitive then you should include either the
first choice encountered, the last choice encountered or all capital letters.

5. Before the program ends, it must reclaim the tree! You can do this by performing a post-order
traversal, i.e., reclaiming the children nodes before reclaiming the node itself. Make sure you
also reclaim the memory occupied by the string as well.

6. It is required that you use getopt for processing the command line and use malloc or calloc and
free functions for dynamically allocating and deallocating nodes and the buffers for the strings. It
is required that you implement your own string comparison functions instead of using the
corresponding libc functions.

Here’s an example:

bash$ cat myfile
bob is working.
david is a new hire.
Bob is working.
alice is bob’s boss.
charles doesn’t like bob.

bash$ ./bstsort myfile
1 alice is bob’s boss.
2 bob is working.
1 charles doesn’t like bob.
1 david is a new hire.

Please submit your work through the inbox as one zip file. Follow the instructions below carefully (to
avoid unnecessary loss of grade):

You should submit the source code and the Makefile in the zip file called FirstnameLastnameA1.
One should be able to create the executable by simply ‘make’.

The Makefile should also contain a
‘clean’ target for cleaning up the directory (removing all temporary files and object files). Make sure
you don’t include intermediate files: *.o, executables, *~, etc., in your submission. (There’ll be a
penalty for including unnecessary intermediate files).

Only two files should be included unless
permission is given for more, those would be bstsort.c, and Makefile. If you feel a need to include a
bstsort.h file, please send me a note asking for permission.

Late submissions will have a deduction as per the syllabus.

• If the program does not compile and do something useful when it runs it will not earn any credit.
• If a program is plagiarized, it will not earn any credit.
• If a program uses a bstsort.h file without permission it will not earn any credit.