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;;For this assignment you will have to investigate the use of the C++ random generator function, rand(). Rand() produces a random integer in the range of 0 to RAND_MAX (a constant -- often 32767 -- defined in the stdlib, automatically included in all of your projects). You can find this in the text or using the online resources given in the lectures.;OPTION A (Basic) A Slot Machine Simulation;Understand the Application;What it Looks Like to the User;The program will loop, asking the user for a bet amount from 0 to 50 (assume dollars, you can use ints or longs). If the user types a 0 that means she wants to quit. Otherwise, accept the amount as their bet and simulate a slot machine pull. Your program will print out a line that looks like a slot machine result containing three strings. Some examples are: BAR 7 BAR, 7 7 cherries, cherries BAR space, space BAR BAR, or cherries cherries BAR.;Each of the three positions in the string could be one of the following: " BAR ", " 7 ", " cherries " or " space ".;Each of the three output positions is must be generated by your program randomly with probabilities;BAR (40%);cherries (30%);space (5%);7 (25%);Therefore, BAR should be the most frequent symbol seen and space or 7 the least frequent.;The following combinations should pay the bet as shown (note ORDER MATTERS);cherries [not cherries] [any] pays 5 ? bet (5 times the bet);cherries cherries [not cherries] pays 15 ? bet;cherries cherries cherries pays 30 ? bet;BAR BAR BAR pays 50 ? bet;7 7 7 pays 100 ? bet;After the pull, display the three strings regardless of the outcome. If the user did not win, tell him/her "Sorry, you lose." If he won, pay him by displaying his winnings (his original bet times the winning factor from the above table). Then, repeat the whole process by requesting another bet amount.;Position counts! If you read the above bullet that contains the warning "ORDER MATTERS", you will see that cherries bar cherries pays 5? while cherries cherries bar pays 15? and bar cherries cherries pays nothing.;A Helper Class: TripleString;We create a new data type to use for this assignment: class TripleString. TripleString will consist of three private member strings as its basic data: (string1, string2, and string3). There will be few instance methods to support that data. The class will be very modest. Once defined, we will use it to instantiate TripleString objects that can be used in our main() method and/or the global-scope methods that main() invokes to simulate this casino project.;The Global-Scope Client Methods;Each global-scope method that you have to write to simulate this casino app plays a special role. For example, there will be one method that gets the bet from the user and returns it to main();int getBet();Another method will simulate a random pull of the slot machine -- it generates three random strings and returns them as a TripleString object to main();TripleString pull();An output method will be used at the end of each loop-pass when the user needs to see the results of her pull, and receive the news about how much she won (or not);void display (TripleString thePull, int winnings);We will describe each method -- and a few others -- in the next section.;The Program Spec;Class TripleString Spec;The first step in writing this program is to create a simple, working class TripleString.;The Data;It will contain three private member strings as its main data: string1, string2, and string3. We will also add a public static member which is to be a const int MAX_LEN set to 20. This represents the maximum length that our class will allow any of its strings to be set to. We can use MAX_LEN in the TripleString method whose job it is to test for valid strings (see below).;In summary, three private instances strings and one public static MAX_LEN. That's all the data for this class.;Default Constructor;TripleString() -- a default constructor that initializes all members to "". We do not need any parameter-taking constructors.;A Private Helper Method;bool validString(string str) -- a helper function that the mutators can use to determine whether a string is legal. This method returns true if its length <= MAX_LEN and false, otherwise.;Mutators/Accessor;set() s and get() s for these members.;Where it All Goes;There are now a variety of program elements, so let's review the order in which things appear in your.cpp file;1. includes and namespace;2. class prototype(s);3. global-scope method prototype(s);4. main() definition;5. global-scope method definition();6. class method definition(s);After writing this class, test it using a simple main() which instantiates an object, mutates the members, displays the object, etc. Don't turn this test in. It's part of your development cycle.;The Global Scope Method Specs;int getBet();This prompts the user for input and returns the bet amount as a functional return. It should vet the amount before it returns and insist on a legal bet (0 < bet < 50) until it gets one from the user. This method loops. If any other method is used to test for an illegal value or output an error message based on an illegal value, there will be a 4 point penalty. getBet() must return the legal value to the client and not take any other action besides getting the legal amount;TripleString pull();This method instantiates and returns a TripleString object to the client. The data of the TripleString object has to be filled with three randomly chosen strings according to the probabilities described in the "Understand the Application" section above. For example, it might return a TripleString object that contains the three strings ["cherries", "BAR", "space"].;The way it determines and loads the three strings is by using another global scope helper method, described, next, randString(). So this method, pull() will call the next method randString() three times to get the three strings that will be stored into the TripleString object. Once that's done, pull() just returns the TripleString object to the client and its job is done.;string randString();This helper method does a little work -- yet is still quite short. It produces and returns a single random string based on the required probabilities. It does this by calling the C++ rand() function and using the return result of that function as a means of deciding which of the four possible strings to return. Take this in stages. rand() returns an int between 0 and RAND_MAX. One idea (but not the only one) is to turn that into an int between 1 and 1000 using techniques from five weeks ago. Then, decide which of those numbers should trigger a "7", which should trigger a "cherries", etc. based on the desired probabilities. Since a "Bar" should happen 40% the time, which numbers would you want to trigger a "Bar"? Since a "cherries" should happen 30% of the time, which numbers would trigger a "cherries"? So you see, this is a very simple -- and even short -- function, even though it has to be designed carefully. Common sense will go a long way here.;int getPayMultiplier (TripleString thePull);After main() gets a TripleString object from pull() (which I will call thePull), it needs to know what the payout will be. That's the job of this function, getPayMultiplier(), which takes the TripleString result from pullString() (thePull) as a parameter, and inspects it to determine what its pay multiplier should be: 5? 15? 100? 0? It does this by looking at the three strings inside the passed-in TripleString object and using if statements to determine and return the right value. For example, if all three of the strings are "cherries", which is easily checked using an if statement, then this method returns a pay multiplier of 30. You can use logic like this to create a sequence of if or else if statements that will give yo

 

Paper#68148 | Written in 18-Jul-2015

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