Description
1 Objectives
1. Gain familiarity with inheritance and polymorphism
2. Gain familiarity with c++ standard library containers
3. Gain familiarity to state-machine program control flow
2 Tasks
1. Download the TextGame.zip file from the course webpage and unzip it into a folder called Lab 11.
2. Study the code and review the program structure:
(a) You can compile the code with the provided Makefile.
(b) The main game loop (in main.cpp) tracks the current GameState object
i. This class uses a std::map object to hold the user choices. You can think of a std::map
as a set of objects of type std::pair
in the pairs.
ii. See http://en.cppreference.com/w/cpp/container/map for the documentation.
(c) Each iteration of the main game loop executes the printOptions method of the current state
(d) The user input is then passed to the handleInput method of the current state, and the return
value is stored as the new currentState
(e) The parent class is GameState which declares some functions which must be implemented in every
class that inherits from it. One example of such a state is the TravelState. Study this state and
get a feel for how it is used in the program.
3. Open the idlestate.h file and implement it to allow the user to either stay resting, or to get up and
resume walking
(a) You may need to remember which direction the user was walking, and whether there was a
crossroad option. To this end, you may need to add private variables to the IdleState class
4. A better solution to the “resume” problem is to adjust the flow of the program as follows:
(a) In the main function, declare a std::stack
objects
i. See http://en.cppreference.com/w/cpp/container/stack for the documentation.
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(b) Change the handleInput function to no longer return a GameState object, but rather take a
std::stack
current state to push new states onto the main stack as needed.
(c) On each iteration of the main loop, use the stack .top() and .pop() to get and remove the top
pointer of the stack, storing it as the new currentState.
(d) Now when we transition from TravelState to IdleState, we can simply push the old travel state
(rather, a copy of it) onto the stack, and then push the new IdleState.
5. Go through a similar procedure to implement the CombatState
(a) To start, give the user only two options: attack or flee
(b) You will need a private variable to hold the battle data
i. For now, only store some number for the monster health
ii. Also store some number of damage to deal to the monster
(c) If the user chooses to attack, subtract the attack amount from the monster’s health
(d) If the monster drops to zero health, end the combat and congratulate the user. Otherwise, push
an updated CombatState object onto the stack.
6. To trigger the combat, use the combatProbability to “interrupt” the main game loop with that
probability, sending the user into combat
7. Be sure to set combatProbability of the CombatState to zero, so that we can’t get attacked while
already in combat!
8. On your own:
(a) Try creating a class hierarchy to hold the “players” of the game: a LivingEntity, with subclasses
Monster and Player
i. In the respective constructors, you may hard-code certain attributes (attack damage, health
values) or try randomizing them!
ii. Use the Monster in the CombatState as a private variable to store the monster along with
the state
(b) Adjust the handleInput to also take the player object as an argument, so that it can be modified
(e.g. if the player takes damage or gets equipment)
(c) Add monster counter-attacks, to take away from the player health during combat
(d) Let the player re-generate health while they are resting
9. This Lab may be turned in by May 13.
10. If you are interested, you can see a more fully implemented form of this game at https://github.
com/jtanderson/TextAdventure. Feel free to clone the code for yourself, make changes, and submit
code to the main repository!
3 Submission
Upload your project files to the course canvas system in a single zipped folder: To zip on Linux:
1. To zip a single folder into a single archive called “myZip.zip”:
zip -r myZip.zip folderName
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2. To zip multiple files into a zip file called “myZip.zip”:
zip myZip.zip file1.cpp file2.h file3 file4.cpp
Turn in (stapled) printouts of your source code, properly commented and formatted with your name,
course number, and complete description of the code.
Also turn in printouts reflecting several different runs of your program (you can copy/past from the
terminal output window). Be sure to test different situations, show how the program handles erroneous
input and different edge cases.
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