Finally, a receipt is printed on the screen and, after a pause, the process repeats for the next customer.

Transcription

1 1 CS 215 Spring 2019 Project 1 (Version 1 Jan 24) Learning Objectives: - implementing an application using if/else and loops - introductory use of file input and output - validating user input and formatting output General Description: Write a program that simulates the action of a gas pump. At startup, the pump reads a file that contains the number of gallons available and price per gallon of three octanes of gas (High, Medium and Low). This information is then printed on the screen. For each customer, the pump starts by displaying a logo and asking the customer if they are a rewards customer or not. If yes, the rewards number is entered and a per-gallon discount is determined. The customer then selects an octane (H/M/L) and enters a number of gallons, or indicates a fill up. For a fill up, an estimate is simulated as a random number of gallons between 1 and 8. If not enough gas is available to satisfy the customer s request, the number of gallons is changed to the amount remaining in the pump and the customer is informed. The pump then simulates dispensing gasoline by printing the amount dispensed on the screen after each ½ gallon is dispensed, reporting approximately every two seconds, until the number of gallons indicated has been dispensed. Finally, a receipt is printed on the screen and, after a pause, the process repeats for the next customer. The pump technician can shut down the pump by entering shutdown to the question Are you a rewards customer? This is a corporate secret and not to be revealed to the customer. On shutdown, the pump reports the gallons of each octane currently available on the screen, then writes this data along with the current prices per gallon to a text file before ending the program. Specifications: General Formatting: - all floating point values should be displayed and written with 2 digits past the decimal point - when prompted for input, there should be at least one space after the prompt so user input is not jammed up with the prompt. Ex: Enter your age: 19 this Enter your age:19 not this!

2 2 Files: - Input File: named pumpin.txt The first line contains three numbers, the number of gallons in the pump s tank of High Octane, Medium Octane and Low Octane, in that order. The second line contains the price per gallon for each octane in the same order. Example: (we are very low on High Octane in this example only 8.9 gallons left!): Output File: named pumpout.txt Contains the same information and format as the input file, reflecting the data at the time the pump is shut down. - Suggestion: Add these two files to the Resource Files section of the Solution Explorer. This is not required, but may make dealing with the files easier. On Startup: The program should read the six values from the input file and display them formatted as shown in this example. The pump s tanks hold a maximum of gallons each, and the price of gas per gallon will be or less. If the program is unable to open the input file, it should display a message Unable to read input file, pause, and exit the program. You may test this by (temporarily) changing the name of the file to something else. Asking if rewards customer: Display a logo as shown. Make up your own name of the gas station, and include your name somewhere in the logo. Ask the user Are you a rewards customer? (Y/N): Valid responses are Y,y,N,n and shutdown. When an invalid response is entered, display Please enter Y or N.and repeat the question. Repeat this until the customer enters a valid answer. Design Hint: note that at this point, one of two options will happen: the program continues with a customer sale, or the shut down is performed and the program ends. This segment of code acts as Input for a Sentinel-Controlled Loop, where the Sentinel Value is shutdown. See more below.

3 3 Asking Rewards Number and Calculating PPG (Price Per Gallon) Discount: If this customer is a rewards customer, ask the customer Enter customer rewards number: You may assume they will enter an integer number. Calculate the PPG discount as the modulus of the customer number by 10 and add 1. This results in a number Divide this result by 100 to get the discount in cents. Example: customer number = % 10 is is / 100 = 0.10 = PPG discount Of course, if the customer is NOT a rewards customer, do not ask them to enter a number and the PPG Discount is Whether a rewards customer or not, print the PPG Discount as shown in the examples. The $ should line up with the customer s input for both Are you a and Enter rewards.. as shown. Also, print a blank line before displaying the prices per gallon in the next section. Displaying Prices Per Gallon: The prices are the standard prices, read from the input file, minus the PPG Discount calculated. Format the price list as shown here. There should be a blank line above and another below the price list. Selecting an Octane: Ask the user Select octane (H/M/L): as shown in the example. Valid entries are H,h,M,m,L, and l. When the user enters an invalid entry, print Please enter H, M or L. Repeat this until the user enters a valid entry. After a valid entry is entered, print a blank line. Getting number of gallons: Ask the user Enter number of gallons (-1 to Fill it up): You may assume the customer will enter an integer or floating point number. When -1 (or any number less than 0) is entered, simulate the number of gallons as a random number between 1 and 8. Use the rand() function, which returns a random number (use modulus to get a number 0 to 7, then add 1). Report this number as detected by a sensor with the message: Sensor reports g gallons needed to fill up, where g is the random number of gallons calculated.

4 4 Check for empty tanks: It is possible this pump is almost empty for some octane of gasoline. The amount in each tank is read when the pump starts. When gasoline is dispensed to a customer, the amount dispensed is subtracted from the tank s current total. If the number of gallons requested is more than is available, give the customer all the remaining supply by changing the number of gallons requested to the amount left in the pump s tank (emptying the tank). Print Sorry, our tank is nearly empty. We only have g gallons available. Note that if the tank is empty, the amount requested will be 0 gallons and the pump will continue delivering 0 gallons at 0 cost. Simulate Pumping Gas: A message on the total number of gallons pumped so far is printed every 2 seconds. The pump pumps ½ gallon every two seconds. Note that the last message should report the original number of gallons requested, and so may not be an equal ½ gallon. One way to get a Visual Studio C++ program to wait (this may not work in other versions of C++) is to use the Sleep(n) function, where n is the number of milliseconds (note the capital S). To use this function, the program must #include <Windows.h> Start with the message Pumping gas... with a blank line before and after the set of messages. Printing a receipt: Format the receipt as shown here, including lining up the values as shown. The octane value printed should NOT be simply H, M or L as originally entered by the user, but should be fully-spelled out as High, Medium or Low. The decimal points for the PPG and total cost should always line up. You may assume no one purchase will exceed $ Feel free to change the text on the Thank You line, but it must have a Thank You line. There should be a pause after printing the receipt. After the pause, the process should repeat for the next customer, staring with printing the logo.

5 5 Shut Down: When the user enters shutdown when asked Are you a rewards customer, the pump performs the following shut down operations and the program ends. It should print the current tank readings (the number of gallons in each of the three tanks) as shown in the example. It should also write the tank readings on one line, and the three price-per-gallon values on a second line, to a file called pumpout.txt See details on files above. Finally, the program prints Pump shut down and then does a pause before the program ends. Style and Grading Rubric: All of this program will be written in the main() function (if you want to divide it into functions, and now how to properly do it, go ahead. But don t forget: NO GLOBAL VARIABLES ALLOWED.EVER!) You should use only coding constructs introduced in this class. If you wish to use other C++ statements, libraries, functions, etc., the instructor for permission! Failure to get permission may result in significant points off your grade. Follow the style rules found on the course website % of your grade will be based on following the style rules. Important: the comments at the top must include the I received help from. section; if it does not, there will be a significant penalty. A general grading rubric will be added to the project on Canvas. It will be used to enter the grade for the project. Submit: You will only need one.cpp file for this project; submit that.cpp file in Canvas. My executable: An executable (proj1.exe) is provided on the course website. It only works on a Windows machine, Version 7 or higher. Your virus protection software may freak out when you try to download this. Hopefully, you are able to tell it to download it anyway. After downloading the.exe, you must also download the pumpin.txt file into the same folder otherwise, the.exe will not be able to find it. Extra Credit: if you find a bug/error in the.exe, be the first to report the problem and earn a couple of extra credit points on the project. Be the first to kwjoiner@cs.uky.edu and report the problem.