As always, if you work on your own, you're expected to do the work on your own, but you can talk about high-level details with others (documented in your README file).
For this assignment you will write two programs
prompt> animal file name for game: animal.dat Does it have feathers [y/n] yes Does it live in a barnyard [y/n] yes is it a(n) chicken [y/n] yes I win!!! Play again? [y/n] yes Does it have feathers [y/n] n Is it a mammal [y/n] y does it have stripes [y/n] n does it hop [y/n] n is it a(n) elephant [y/n] n I give up, what animal were you thinking of: lion What question has a yes answer for a(n) lion and a no answer for a(n) elephant. does it have mane Play again? [y/n] yes Does it have feathers [y/n] n Is it a mammal [y/n] y does it have stripes [y/n] n does it hop [y/n] n does it have a mane [y/n] yes is it a(n) lion [y/n] y I win!!! Play again? [y/n] no Thanks for playing twenty questions. Write data to what file? [animal.dat] an2.dat
Question Yes Answer (left subtree) No Answer (right subtree)
Questions are identified by the three-character string #Q: at the beginning of a line, lines that do not begin with the string #Q: represent answers/animals.
For the run above, the sample file animal.dat is reproduced below.
#Q:Does it have feathers
#Q:Does it live in a barnyard
chicken
#Q:is it wise
owl
#Q:does it gobble
turkey
#Q:does it say "Nevermore!"
raven
eagle
#Q:Is it a mammal
#Q:does it have stripes
tiger
#Q:does it hop
kangaroo
elephant
gila monster
The tree that corresponds to this file is shown below. You'll need to construct a tree like this in the program you write. Note that yes answers in the tree are shown as left/blue arrows, no answers are right/red arrows.
The code in treeread.cpp shows how to read a tree from the tree's pre-order traversal. The treeread.cpp program uses free functions (not in a class) and reads from cin/standard input. For example, here's a run on the data file tree.dat.
prompt> treeread < tree.dat in order traversal dingo fox giraffe platypus racoon rhinoceros tasmanian devil tiger warthog pre order traversal platypus fox dingo giraffe tiger rhinoceros raccoon tasmanian devil warthog
Note that the format of the data file used above is similar (though not identical) to what you'll be writing for the animal guessing game program.
As shown in the example run above, the user is prompted for a filename in which the tree/game will be saved. The default filename is the one the user originally entered, but in the run above a different name is used. It's a good idea to use a different name for the file until you know your program works.
You'll probably want to write more functions than these. The functions you write must be in a class AnimalGame. You may decide to use other classes, that's fine, but you must create at least one class and use it in the main function of the version of animal.cpp that you write. The declaration for the TreeNode class you use must be private to the AnimalGame class.
So, a private function build could appear in the header file as follows.
Note that the function name is qualified using AnimalGame:: just as the struct name is qualified, though both appear in the header file without the qualifier.
If the Tree struct is private to AnimalGame, the public member functions cannot use Tree as a return type or as parameters of the public functions. Instead, the public functions will call private helper functions that do the work.
In general, classes in which trees are used will often have one private, helper function for each public function. The public function implementation calls the private function which does the work.
For example:
When you use cin >> s the extraction leaves the newline character (entered when you press return) on the stream. When you call getline the character is read and you'll get an empty string as a result of the getline. See page 410 in Chapter 9 of Tapestry for a more complete explanation.
Summary: If you use getline, don't use >> input. You might want to use getline because it allows the user to enter complete sentences including spaces.
Your final executable should be named animal. Your final program should consist of at least animal.cpp, animalgame.h, and animalgame.cpp. The Makefile you're given has entries for being able to type make animal from animal.cpp and animalgame.cpp, but you should run make depend before compiling/creating animal since there are no files named animal.cpp and animalgame.cpp in the code you're given.
You may decide to write the code without using a class at first, or using a class but not creating separate .h and .cpp files. However, your final program needs to have separate .h and .cpp files.
This assignment is worth 25 points, the breakdown is as follows:
| functionality | points |
|---|---|
| read file into tree | 4 |
| play game/add info to tree | 5 |
| save file properly | 4 |
| coding style/classes | 5 |
| data file created | 2 |
| README | 3 |
| deleting nodes | 2 |
You must also submit a README file in which you list all the people with whom you collaborated, and the TAs/UTAs you consulted with. You should include an estimated of how long you spent on the program and what your thoughts are about the assignment.
You must create a sample data file whose name indicates something about its contents. The questions should be yes/no questions about any topic, e.g., animals, elements from the periodic table, courses at Duke, and so on.
To submit use Eclipse or enter the following on acpub:
submit_cps100 animal *.h *.cpp Makefile README foo.dat
Do not submit .o or .exe files.
Where the foo.dat file is the file of yes/no questions you created for this assignment. Failure to submit a working Makefile will cause you to lose 5 points.