The Objective

The Background

We used a very simplistic (and unrealistic) approach to the problem of singing karaoke in project 3. In that project we had 10 singers and each singer had 10 songs. All of the singers were present at the beginning of the night and stayed until closing and were taken in the order they appeared in the data file. The data files were also set up so that no singer could sing a song that someone else had already sung, since no song titles were repeated. We all know that it doesn't happen this way.

This project will simulate karaoke in a much more realistic manner. Singers can come in at any time during the evening and be added to the rotation at that time. Singers may also leave at any time and should be removed from the rotation at that time. It is possible that several singers might have the same song in their song list. In reality, the karaoke host will not let a singer sing a song that someone else has already sung that evening.

The Task

Then you will read from the events.dat file and store the information in an array of EVENTS called events. The events are in order by the time they occur and consist of the time, a singer's name, and whether the singer is ENTERing or EXITing. The first number in the file is the number of events in the file.

Although it might be nice to print out all of the singers slips when s/he first arrives, we'll assume that has already been done to shorten your output.

To simulate the evening, you must keep track of the time. We will be working in intervals of 5 minutes, as before, and assume that a person can sing a song in 5 minutes. The evening of karaoke will be from 8:00 PM until 1:30 AM. All times given in the events file are guaranteed to be on a 5 minute interval. Several events can happen at the same time. You should handle all of the events in the events array for the current time and then let a singer sing in that time interval as well. (See sample output)

A singer is to randomly choose a song from his list of songs but cannot sing the same song again that evening. A singer also may not choose a song from his list that has been sung by someone else that evening. You must have an array of strings of sungSongs that can be checked for the song title to avoid repeats. You must use the song title for this, not the song number, since more than one artist might have recorded a song and those different renditions are considered to be the same song even though they would have different song numbers. If the randomly-chosen song is a song that has already been sung, randomly chose another song.

As new singers arrive (ENTER), they are to be removed from the list of singers and added to the end of the rotation linked list and as they leave (EXIT), they should be removed from the rotation list and put back into the list of singers.

As always, you should have several debugging functions that you can call during the implementation stage of programming to make sure that each list contains what it should, that you managed to read properly from the files, etc.

Since singers now have different numbers of slips, you can no longer just have an array of SLIPs of size 10 in the SINGER structure. You should have a member that contains the number of slips and you'll need to dynamically allocate the space needed to store that many SLIPs. This memory's address should be stored in the structure and can be used as an array. Some of the songs now have longer titles, so the size of a title should now be 40.

More details

• You must use the following structure definitions : typedef struct slip { char singer[SINGER_NAME_SIZE]; char title[TITLE_SIZE]; char songNumber[SONG_NUMBER_SIZE]; int sung; } SLIP; typedef struct singer { char name[SINGER_NAME_SIZE]; int timesSung; int numSongs; SLIP* slips; } SINGER; where,
  • SINGER_NAME_SIZE needs to be #defined to be 15
  • TITLE_SIZE needs to be #defined to be 40
  • SONG_NUMBER_SIZE needs to be #defined to be 12
  • slips is still to be used as an array of SLIPs, but the space will need to be dynamically allocated for them depending upon the number of slips each singer needs.

  You must also have a struct of type EVENT. The definition is up to you.

• You must use command line arguments for this program. The first is to be the name of the singers file, p5karaoke.dat, the second is the name of the events file, events.dat, and the third is the positive integer to be used as the seed for the random number generator.

• Since many students have encountered problems in the past using the function feof() when trying to detect EOF, please use one of the methods shown in the slide "Knowing when to stop" from the Streams lecture.

• Since each singer is to randomly choose from amongst their own songs, you'll need to use the random number generator. You MAY NOT seed the random number generator with a call to time() for this project. You must use the number entered on the command line as the seed This is necessary for testing purposes by the graders.

• Your program should simulate the singer choosing a song randomly from his/her songs as it becomes his turn to sing. Remember that songs cannot be repeated in the same evening, whether or not it was sung by this singer.

• Your program should do whatever bookkeeping is necessary as the song is sung. (Mark the song as sung, copy its title into the array of sung songs, increment timesSung, etc.) Keep in mind that before you can copy a song title into the array of sungSongs you must first dynamically allocate the space to hold it.

• This process should continue allowing the singers to sing one song each per rotation in their turn until Karaoke ends for the evening.

• You must write a function called DestroyList() which goes through a list free()ing each of the nodes and then makes the list an empty list again. The following prototype is required and may not be changed: void DestroyList (NODEPTR *headPtr);

• Your program must close all files used as soon as it's finished reading from them.

• Your program must free all memory that was dynamically allocated as soon as that memory is no longer needed.

The data files

The name of the data files are p5karaoke.dat and events.dat and can be viewed from this link. You should NOT view it and save it into a file or cut and paste it from the browser into a file. Either of these methods of obtaining the file may cause there to be extraneous characters in the file that your program will try to read and disrupt the input of your data. Instead you must copy the file from my directory into the directory that you'll be using to work on this project.

Go to that directory and then issue the following commands exactly :

cp /afs/umbc.edu/users/b/o/bogar/pub/p5karaoke.dat .

cp /afs/umbc.edu/users/b/o/bogar/pub/events.dat .

The space and the . (dot) at the end of the command are necessary and a part of the command.

Sample Compilation

Sample Output

Extra Credit

For 5 points of extra credit, sort the array of sung songs and use binary search (rather than linear search) to determine if a song is in the array or not. Submit a file called README that tells the grader that you implemented the extra credit portion.

What to Turn In

You must use separate compilation for this project and should have a file, called proj5.c, that contains only the function main(). You should also have karaoke.c and karaoke.h, that contain functions related karaoke and the prototypes for those functions, respectively. You may, of course, have other .c and .h files, as you see fit. You should realize that you will be reusing some functions that you wrote for previous projects and they should have been either in your karaoke.c file or in your util.c file. Many of you will be able to reuse the util.c and util.h files. You may use the linked list code from the lectures and it will work with only minor modifications.

Submit as in previous projects. Don't forget your .h files.