Solved–Assignment 0 –Solution

Description

You have been given a file “SongCSV.csv” which contains comma separated
data on separate lines. You are to read that file and create a struct for each
song that includes: Artist, Name of Song, Album Name, Duration, Year of
Release, and Hotttnesss.

For the first song in the file

1,”SOCJJDX12A8C13E745″,222209,”Aswad vs. The Rhythm
Riders”,”ARP39OU1187FB4D543″,,”West London
England”,,”Aswad”,0.0,258.42893,1,0.69,199.826,nan,7,0.32,”Rudeboy”,0

the relevant fields are Aswad, Rudeboy, Aswad vs. The Rhythm Riders,
258.42893, 0, and nan(enter 0.0). Artist, Name of Song, and Album Name
is stored as char *,Duration is a float, Year of Release is an integer, and
Hotttnesss is a double

You will dynamically allocate memory for each struct as the file is processed.
An array of pointers to these will be managed so that searching can be
accomplished (binary search because you sorted the pointers).

You will fopen() the file, and then use the I/O operations from Chapter 5
(standard library) in Stevens to process the file (fgets(), fclose(), feof() etc ).
You may use strtok_r() from the string libraries, as well as atoi() and atof().

Think of this program as a step towards something larger. Demonstrate that
your program works by searching the array for a given song and outputting
the struct data. Make a typescript (use utility ‘script’) of this performance
by searching with the following keys:

For the output you may use fprintf() to stdout. We will test this ourselves,
but for the moment take user input (the song name) and use it to search the
sorted structs using … ! … binary search.

This assignment will ultimately be on the jazz server … a work in progress.
I hope we can have all of this taken care of quite soon.

Basic Algorithm Flow:

1Open the csv file

2 Extract lines, one at a time.

Put relevant fields (see above) into a struct which is then put into an
array of structs. Please note that you are required to allocate memory
for structs dynamically.

3 Sort the array of structs by song name. (You may have been doing this in
step 2)

4) Create user interface to search for songs by song name Display relevant
data to user in a neat format Exit only when user enters ZZZ (not ‘Quit’ or
‘q’ or ‘Q’ or ‘exit’ or ‘Exit’ or ‘EXIT’ or ‘Leave” or anything other than ZZZ)

We have provided a make file for you and a sample testing input file (we
will cleverly use a different one for actual testing). If your program does not
work with ‘make && make test’ we will not be able to test your program,
and you will not like your grade.

Also, would you please push only the source code and typescript of
performance. Please do not push back the various files that have been
provided to you (e.g. syllabus).

Discussion

The intent of this assignment and the next is to immerse you in the C / Unix
system programming environment with the good, bad, and ugly of it all. A
number of issues are worth mention (in no particular order here).

0) YOU MUST HAVE A LAPTOP RUNNING UNIX. Although you can
survive with a VM , it offends me that you don’t have something more
permanent – just old fashioned. Have the wizards help you dual boot.
Bring your machine to class.

I) C and standard library issues
1) Pointers – love the asterisk. Know how to declare, instantiate i.e.
make the pointer point somewhere, dereference and assign
values to the ‘pointee’. Understand that because C as a language
is limited the ‘*’ shows up in parameter passing, strings (char *),
and function returns of compound data structures (arrays,
structs). Understand that arrays are synonymous with pointers
and that pointers can be subscripted cuz why not ?
2) dynamically allocated memory via malloc(), calloc(), realloc()
requires using pointers.
3) Structs and pointers – fields are referenced with . or -> depending
on how you have access to the struct. Structs can be copied
wholesale.
4) The string functions all use char * references with a null
terminator. strlen() does not count the null but allocating memory
for a strncpy() requires that extra byte. Be careful with strtok_r().
Use the ‘n’ versions of string functions (strncpy() vs strcpy() ),
Use the _r versions (‘reentrant) of functions.
5) Standard library I/O use the ‘f’ library routines built upon the
non-f system calls: fopen() vs open(), buffered streams vs
unbuffered references via file descriptors; formatted fprintf() vs
unformatted write().

II) From Source to Executable the Unix Way
The steps of creating programs: cpp, gcc (translate), gcc (load via
ld), and then execute. Make files automate the above. Source code is
‘pre-processed’ to take advantage of #include directives and good
software practice
III) Use The Utilities
Use utilities such as script, make, valgrind , and gdb – NOW. Your
life will be easier if you invest in minimal mastery of these tools.
Make automates command line source code management. Valgrind
insures you don’t have pointers going astray and often reveals
bugs. Gdb allows you a debugger. Script lets you document
program behavior. Each has its idiosyncracies.

IV) The Assumed Stevens Working Environment
You may use an IDE if you wish but we will assume command line
capability. Use gedit for screen editing capabilities. Be able to
navigate and reproduce Stevens code.
The Stevens environment. “apue.h” and the companion source code
“error.c” are used throughout Stevens’ source code. Use these
because then you can reproduce his examples. I will provide copies
of apue.h, error.c, and all of the source code in the text. You must
test all system call return values so use Stevens’ error routines as a
habit. See Ch1 for the errno, perror() scheme provided in all Unix
environments.