辅导案例-CMPT 120-Assignment 4

  • August 9, 2020

1 Simon Fraser University CMPT 120: Assignment 4 The objective of this assignment is to improve the “travel agent” bot from Assignment 1. Problem Description In this assignment we want to improve the “travel agent bot” from Assignment 1. The goal is to easily extend the bot to incorporate new destinations (in addition to Vienna and Bali) and additional “highlights” (in addition to “classical music” and “beaches and surfing”) by means of using files and representing them as lists. Also, the program’s structure ought to be improved through the usage of functions, and user inputs ought to be validated. As before, the bot will first display a welcome message. Then it will ask for the user’s name and age. If the user is 65 or older, it will inform them about a senior discount. Next, it asks how long (how many nights) 2 the trip is going to take. Then it interviews the user about whether they like or dislike the various “highlights” that the destinations may or may not have. Based on the user’s replies, it will suggest and display the costs of one trip the travel agency currently offers or say that they don’t have any offers matching the user’s preferences. As before, the bot will then ask the user whether they are interested (even if no offer was shown). If that is the case, the bot will provide a one- time password for the user to enter on the travel agency website. If the user is not interested, the bot will just say goodbye. Then the program will end. Stage 1: Restructure the Previous Chatbot This assignment will work in two stages. In the first stage, the chatbot from Assignment 1 is to be restructured to make use of functions, but without changing the program’s behavior. For this part, you may use the sample solution provided for Assignment 1 in Canvas. Rework the program to define and call the following functions: 1. welcome: Purpose: Displays the welcome message. Arguments: none Returns: nothing 2. ask user information: Purpose: Asks the user for their name, age, and how many nights they want to stay. Arguments: none Returns: the user’s name (a string), age (an integer), and the number of nights (an integer) 3. ask user preferences: Purpose: Asks the user whether they like classical music, and whether they like beaches and surfing. Arguments: none Returns: whether the user likes classical music (a Boolean), and whether the user likes beaches and surfing (a Boolean) 4. ask yes no: 3 Purpose: Displays a question to the user and prompt them to type in either “y” or “n”. (Here, it won’t be necessary to cover all variations of “yeses” and “noses”. Any response other than “y” and “n” can be interpreted as “no”.) Arguments: the question (a string) Returns: whether the user responded positively or negatively (a Boolean) 5. ask number: Purpose: Displays a question to the user and prompt them to type in a number. Arguments: the question (a string) Returns: a number typed in by the user (an integer) 6. compute discount percentage: Purpose: Determine discount in terms of percentage points the user gets for their age. Arguments: age (an integer) Returns: the discount percentage (an integer) 7. compute total cost: Purpose: Computes the total cost of a trip. Arguments: the price for the flight (a float), the price for the hotel (a float), the number of nights (an integer), and an age (an integer) Returns: the total cost (a float) 8. show trip details: Purpose: Displays the information for a trip. Arguments: the destination (a string), the price for the flight (a float), the price for the hotel (a float), the number of nights (an integer), the user’s age (an integer) Returns: nothing 9. suggest trip: Purpose: Chooses one destination to suggest to the user. Arguments: whether the user likes classical music (a Boolean), whether the user likes beaches (a Boolean), the cost of a trip to Vieanna (a float), and the cost of a trip to Bali (a float) 4 Returns: the string ”Vienna”, or the string ”Bali”, or the value None, according to the rules for suggesting a trip from Assignment 1: If the user prefers culture over beaches, the bot will suggest the trip to Vienna. In case they prefer beaches over culture, they will suggest the trip to Bali. If they like both, the bot will try to maximize the travel agency’s profit by recommending whatever trip has the highest total costs (if both cost the same, Bali is chosen). 10. ask to create account: Purpose: Ask the user whether to create an account. If they answer positively, display the one-time password. Arguments: none Returns: nothing Restructuring the program should be an iterative process. This means that you should always only change a small piece of code, say by defining a single new function, and then run the program and test whether it still works as before, for example by following the provided sample runs. Only once you have eliminated all new errors that perhaps occur, move on to change the next thing. When implementing a new function, also make sure that you identify the various parts of the program from which the function is to be called. Remember that it is possible for one function to call another function. If some piece of code is identical or very similar to the body of a function body, then this strongly indicates that instead the function should be called at that point. For example, notice that the functions ask user preferences and ask to create account involve asking the user yes/no questions, which should be done by means of calling the ask yes no function. Sample Runs for Stage 1 What the user types is underlined and highlighted. The sample runs below are essentially the same as for Assignment 1.1 ============ Sample run 1.1 ============ Welcome ! I am your friendly travel agent bot . 1The only changes are that since “culture” is a very broad term, the feature “culture and classical music” has been renamed to “classical music”, and that prices are rounded, so as to display 1860.97$ instead of 1860.9699999999998$. 5 I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Alice Hello dear Alice ! What is your age ? –> 23 For how many nights do you want stay ? –> 6 Do you like classical music ? Please answer y/ n. –> y Do you like beaches and surfing ? Please answer y/ n. –> n How about a trip to Vienna ? Flight : 997 . 93 $ Hotel : 143 . 84 $/ night Discount : 0% Total for 6 nights ( incl . discounts ): 1860 . 97 $ Are you interested , and want to create a user account ? Please answer y/ n. –> y Looking forward to working with you ! Your one – time password is: eeeeeee A Goodbye . ============ Sample run 1.2 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . 6 What is your name ? –> Bob Hello dear Bob ! What is your age ? –> 71 Great ! We offer a senior discount . For every year over 64 , you get 1% off . For how many nights do you want stay ? –> 10 Do you like classical music ? Please answer y/ n. –> y Do you like beaches and surfing ? Please answer y/ n. –> y How about a trip to Bali ? Flight : 849 . 93 $ Hotel : 235 . 35 $/ night Discount : 7% Total for 10 nights ( incl . discounts ): 2979 . 19 $ Are you interested , and want to create a user account ? Please answer y/ n. –> n Sorry to hear that . Please consider using our service again . Goodbye . ============ Sample run 1.3 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Cathleen Hello dear Cathleen ! What is your age ? –> 42 7 For how many nights do you want stay ? –> 7 Do you like classical music ? Please answer y/ n. –> y Do you like beaches and surfing ? Please answer y/ n. –> y How about a trip to Bali ? Flight : 849 . 93 $ Hotel : 235 . 35 $/ night Discount : 0% Total for 7 nights ( incl . discounts ): 2497 . 38 $ Are you interested , and want to create a user account ? Please answer y/ n. –> y Looking forward to working with you ! Your one – time password is: nnC !!!! Goodbye . ============ Sample run 1.4 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Doug Hello dear Doug ! What is your age ? –> 99 Great ! We offer a senior discount . For every year over 64 , you get 1% off . For how many nights do you want stay ? –> 5 Do you like classical music ? Please answer y/ n. –> n 8 Do you like beaches and surfing ? Please answer y/ n. –> n I Im sorry , we don It have any trips to offer at this point . Are you interested , and want to create a user account ? Please answer y/ n. –> n Sorry to hear that . Please consider using our service again . Goodbye . Stage 2: Include More Destinations and Highlights In the second stage, new destinations and highlights are to be incorporated by means lists, to be read from files. Create a copy of your solution to stage 1, and revise it as follows. Destinations Now, the travel agency offers multiple trips, for example with the following prices: Destination Flight Hotel (per night) Vienna $997.93 $143.84 Bali $849.93 $235.35 Las Vegas $338.37 $173.54 Macao $734.34 $199.99 To represent this data in the program, use a list destinations that holds the names of the destinations (as strings) as well as lists flight prices and hotel prices of the same length that hold the corresponding prices for flights and hotels, respectively. Note: When grading the assignment, different values from the ones provided here might be used. Your solution should still work when these lists are changed or extended. To receive bonus points, read this data from the .csv files provided with this assignment instead of hard-coding them (see below). Since the three lists are of the same length and follow the same order, this will allow us to access the flight or hotel price of a destination by means of their index, i.e. their position in the list. For example, when Las Vegas is at the third position and thus has index 2 in list destinations, 9 flight prices[2] will give us the price for the flight to Las Vegas. Revise the following functions accordingly: • compute total cost: Purpose: Computes the total cost of a trip. Arguments: the destination (a string), the number of nights (an integer), and an age (an integer) Returns: the total cost (a float) • show trip details: Purpose: Displays the information for a trip. Arguments: the destination (a string), the number of nights (an integer), the user’s age (an integer) Returns: nothing Highlights The travel agency now distinguishes several highlights, for example “classical music”, “beaches and surfing”, “history and architecture”, “gambling”, and “musicals”. Use a list called highlights that contains such strings. Again, your solution should still work when different values are used, and for bonus points have your program read them from the corresponding .csv file. Then revise the function ask user preferences to use a for loop to iterate over the highlights in this list, asking the user whether they like them in each case. The function should now return a list of Boolean values, one for each highlight. Matching Highlights The following table shows an example of which of the destinations offers which of the highlight features: classical music beaches and surfing history and architecture gambling musicals Vienna ✓ ✓ Bali ✓ ✓ Las Vegas ✓ ✓ Macao ✓ ✓ To represent this information, use a list dest_highlights that contains for each destination a list of Boolean values indicating whether the destination 10 offers the corresponding highlights. dest_highlights is hence a list of lists. The outer list has the same length as list destinations (4), and each of its elements is itself a list of the same length as highlights (5). Again, ensure that your solution works for different values, and for bonus points make your program read them from a file. For matching destinations to user preferences, revise the function suggest trip as follows: • suggest trip: Purpose: Determine which destination which “matches” best to the user preferences, i.e., the number of positions where both lists contain True. Arguments: a list of Boolean values, representing the user preferences Returns: a string, representing a destination The bot ought to suggest whatever destination offers the most features that the user prefers. In the above example, if the user likes “beaches and surfing”, “history and architecture”, and “musicals” (and none of the others), it will suggest Bali, as it matches 2 preferences. In the program, this means that the destination whose list in dest_highlights has the most True values at the same positions as the list representing the user’s preferences is the best match (False values at the same position don’t count). When there are multiple destinations with the same, maximal match count, the one that comes first in list destinations is chosen. To keep things simple, we don’t “tie-break” by comparing the total costs anymore. Only if the number of matches comes out zero, which can only happen when the user said “no” to each one of the highlights, the bot will respond saying “I’m sorry, we don’t have any trips to offer at this point” (see sample run 2.3). Note that for this part of the program, you will have to make use of a list of accumulators, each element being the number of matches for one of the destinations. Computing the matches will require nested loops. To determine the maximal match count from the list of accumulators, you can use the built-in function max, but note that you want to determine the position (representing the destination) with the maximal match count, not the maximal number of matches itself. 11 Using Files (Bonus) Reading Data from Files The assignment description in Canvas contains the .csv files (CSV stands for “comma separated values”) destinations.csv highlights.csv flight prices.csv hotel prices.csv dest highlights.csv Make your program read its data from these files for bonus points. You are encouraged to use the interactive textbook as reference to see more details about reading and writing data files, Chapter 11. Still, Python code for both reading and writing data from/to files is provided with this assignment. The function read string list from file(…) takes a string as argument, containing a file name (it is assumed that the file is located in the same folder as your Python program), and returns a list of strings, each of which contains the content of one line of the file being read, in the same order (without the newline character ’\n’ at the end). For example, the call read string list from file(“highlights.csv”) will return the list [“classical music”, “beaches and surfing”, “history and architecture”, “gambling”, “musicals”]. You may develop a different function to read the data. You may incorporate this function verbatim in your code, including the comments. If you revise the function, clarify how you do it. Note that for destinations.csv and highlights.csv, calling the function is enough. For flight prices.csv and hotel prices.csv, the strings have to be converted into floats afterwards. To get the list of lists dest_highlights from the file dest_highlights.csv, each string has to be converted into a list of Booleans, for which you first need to split the string, e.g. using the built-in string method .split(…). Writing Data to Files After the dialog with the user, your program should write the user-specific data (i.e., their name, age, and preferences) to the file users.csv. Here you can use the function append line to file(…) that is provided. It 12 takes two string arguments: the first one is a single string that contains all data to be written, the second one is the name of the file to be written to (again it is assumed that this file is the same folder as your program). The function will append the string as a new line at the end of the file, leaving all previous file contents intact. Running your program multiple times hence will successively add more and more lines to the file, one for each new user. Check the requirements and assumptions in the function code and comments. Use a similar representation for this output data as is used for the input data. That is to say, the different values are separated by commas, and Boolean values are represented by ”1” and ”0”. After the five sample runs shown below, the content of the file users.csv should be: Alice,23,1,0,1,0,0 Bob,71,0,1,1,0,1 Cathleen,42,0,0,0,0,0 Doug,99,0,0,1,1,0 Erica,27,1,0,1,0,1 User Input Validation Revise the function ask yes no such that they validate the user input, and prompt them to type in a new answer until they either types “y” or “n”. Similarly, revise function ask number to prompt the user to type in a new answer as long as their input is not a sequence of digits. See sample run 2.5 below. (Hint: You may want to use the string method isdigit) Sample Runs for Stage 2 The below sample runs incorporate trace messages with the purpose of illustrating how matching is supposed to work. You do not need to include them in your submission. (Of course, you are free to make use of trace message while working on your solution.) ============ Sample run 2.1 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you 13 with a one – time password to create a user account on our website . What is your name ? –> Alice Hello dear Alice ! What is your age ? –> 23 For how many nights do you want to stay ? –> 6 Do you like classical music ? Please answer y/ n. –> y Do you like beaches and surfing ? Please answer y/ n. –> n Do you like history and architecture ? Please answer y/ n. –> y Do you like gambling ? Please answer y/ n. –> n Do you like musicals ? Please answer y/ n. –> n ** Trace : Vienna matches preference for classical music ** Trace : Vienna matches preference for history and architecture ** Trace : matches for destination Vienna : 2 ** Trace : Bali matches preference for history and architecture ** Trace : matches for destination Bali : 1 ** Trace : matches for destination Las Vegas : 0 ** Trace : Macao matches preference for history and architecture ** Trace : matches for destination Macao : 1 How about a trip to Vienna ? Flight : 997 . 93 $ Hotel : 143 . 84 $/ night Discount : 0% Total for 6 nights ( incl . discounts ): 1860 . 97 $ 14 Are you interested , and want to create a user account ? Please answer y/ n. –> y Looking forward to working with you ! Your one – time password is: eeeeeee A !! Goodbye . ============ Sample run 2.2 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Bob Hello dear Bob ! What is your age ? –> 71 Great ! We offer a senior discount . For every year over 64 , you get 1% off . For how many nights do you want to stay ? –> 10 Do you like classical music ? Please answer y/ n. –> n Do you like beaches and surfing ? Please answer y/ n. –> y Do you like history and architecture ? Please answer y/ n. –> y Do you like gambling ? Please answer y/ n. –> n Do you like musicals ? Please answer y/ n. –> y ** Trace : Vienna matches preference for history and architecture 15 ** Trace : matches for destination Vienna : 1 ** Trace : Bali matches preference for beaches and surfing ** Trace : Bali matches preference for history and architecture ** Trace : matches for destination Bali : 2 ** Trace : Las Vegas matches preference for musicals ** Trace : matches for destination Las Vegas : 1 ** Trace : Macao matches preference for history and architecture ** Trace : matches for destination Macao : 1 How about a trip to Bali ? Flight : 849 . 93 $ Hotel : 235 . 35 $/ night Discount : 7% Total for 10 nights ( incl . discounts ): 2979 . 19 $ Are you interested , and want to create a user account ? Please answer y/ n. –> n Sorry to hear that . Please consider using our service again . Goodbye . ============ Sample run 2.3 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Cathleen Hello dear Cathleen ! What is your age ? –> 42 For how many nights do you want to stay ? –> 7 16 Do you like classical music ? Please answer y/ n. –> n Do you like beaches and surfing ? Please answer y/ n. –> n Do you like history and architecture ? Please answer y/ n. –> n Do you like gambling ? Please answer y/ n. –> n Do you like musicals ? Please answer y/ n. –> n ** Trace : matches for destination Vienna : 0 ** Trace : matches for destination Bali : 0 ** Trace : matches for destination Las Vegas : 0 ** Trace : matches for destination Macao : 0 I Im sorry , we don It have any trips to offer at this point . Are you interested , and want to create a user account ? Please answer y/ n. –> y Looking forward to working with you ! Your one – time password is: nnC ! Goodbye . ============ Sample run 2.4 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Doug Hello dear Doug ! 17 What is your age ? –> 99 Great ! We offer a senior discount . For every year over 64 , you get 1% off . For how many nights do you want to stay ? –> 5 Do you like classical music ? Please answer y/ n. –> n Do you like beaches and surfing ? Please answer y/ n. –> n Do you like history and architecture ? Please answer y/ n. –> y Do you like gambling ? Please answer y/ n. –> y Do you like musicals ? Please answer y/ n. –> n ** Trace : Vienna matches preference for history and architecture ** Trace : matches for destination Vienna : 1 ** Trace : Bali matches preference for history and architecture ** Trace : matches for destination Bali : 1 ** Trace : Las Vegas matches preference for gambling ** Trace : matches for destination Las Vegas : 1 ** Trace : Macao matches preference for history and architecture ** Trace : Macao matches preference for gambling ** Trace : matches for destination Macao : 2 How about a trip to Macao ? Flight : 734 . 34 $ Hotel : 199 . 99 $/ night Discount : 35% Total for 5 nights ( incl . discounts ): 1127 . 29 $ Are you interested , and want to create a user account ? Please answer y/ n. –> n 18 Sorry to hear that . Please consider using our service again . Goodbye . ============ Sample run 2.5 ============ Welcome ! I am your friendly travel agent bot . I will ask you some questions , and make a recommendation based on your answer . If you are interested , I will provide you with a one – time password to create a user account on our website . What is your name ? –> Erica Hello dear Erica ! What is your age ? –> 27.5 You didn It type in a ( whole ) number ! Please type in a number ( w/ o decimal point ) –> twenty-seven and a half You didn It type in a ( whole ) number ! Please type in a number ( w/ o decimal point ) –> 27 For how many nights do you want to stay ? –> a week You didn It type in a ( whole ) number ! Please type in a number ( w/ o decimal point ) –> 7 days You didn It type in a ( whole ) number ! Please type in a number ( w/ o decimal point ) –> 7 Do you like classical music ? Please answer y/ n. –> sometimes You didn It type Iy I or In I! Please answer y/ n. –> y Do you like beaches and surfing ? Please answer y/ n. –> nope You didn It type Iy I or In I! Please answer y/ n. –> n Do you like history and architecture ? Please answer y/ n. –> absolutely You didn It type Iy I or In I! 19 Please answer y/ n. –> definitely You didn It type Iy I or In I! Please answer y/ n. –> y Do you like gambling ? Please answer y/ n. –> no way You didn It type Iy I or In I! Please answer y/ n. –> n Do you like musicals ? Please answer y/ n. –> y ** Trace : Vienna matches preference for classical music ** Trace : Vienna matches preference for history and architecture ** Trace : matches for destination Vienna : 2 ** Trace : Bali matches preference for history and architecture ** Trace : matches for destination Bali : 1 ** Trace : Las Vegas matches preference for musicals ** Trace : matches for destination Las Vegas : 1 ** Trace : Macao matches preference for history and architecture ** Trace : matches for destination Macao : 1 How about a trip to Vienna ? Flight : 997 . 93 $ Hotel : 143 . 84 $/ night Discount : 0% Total for 7 nights ( incl . discounts ): 2004 . 81 $ Are you interested , and want to create a user account ? Please answer y/ n. –> n Sorry to hear that . Please consider using our service again . Goodbye . 20 Requirements of Code Organization and Assumptions • Your code needs to follow the general coding guidelines ((https://canvas.sfu.ca/courses/53294/pages/python-source-code-general- guidelines?module_item_id=1494361)) • The text in the dialog (what the users sees) needs to be the same as in the sample runs. • You may include “Trace printing” as you debug your code. When you submit your solution, you may comment out some tracing prints. However, you need to leave in your program tracing print analogous to what is shown in THE SAMPLE RUNS. What You Are Required to Submit • Two Python files, one for each stage, named travelagent2 stage1.py and travelagent2 stage2.py.

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