Description
In this workshop, you implement aspects of linkage, storage duration, namespaces, header guards, and operating system interfaces.
Learning Outcomes
Upon successful completion of this workshop, you will have demonstrated the abilities to: – receive program arguments from the command line guard a class definition from duplication in a translation unit – access a variable defined in a different translation unit – declare a local variable that resides in memory throughout the lifetime of the program – upgrade code to accept and manage a user-defined string of any length
Submission Policy
The workshop is divided into two coding parts and one non-coding part:
Part 1: worth 0% of the workshop’s total mark, is optional and designed to assist you in completing the second part.
reflection: non-coding part, to be submitted together with Part 2. The reflection does not have marks associated to it, but can incur a penalty of max 40% of the whole workshop’s mark if your professor deems it insufficient (you make your marks from the code, but you can lose some on the reflection).
If the file contains only your work, or work provided to you by your professor, add the following message as a comment at the top of the file:
I have done all the coding by myself and only copied the code that my professor provided to complete my workshops and assignments.
If the file contains work that is not yours (you found it online or somebody provided it to you), write exactly which parts of the assignment are given to you as help, who gave it to you, or which source you received it from. By doing this you will only lose the mark for the parts you got help for, and the person helping you will be clear of any wrong doing.
Compiling and Testing Your Program
All your code should be compiled using this command on matrix: bash /usr/local/gcc/10.2.0/bin/g++ -Wall -std=c++17 -g -o ws file1.cpp file2.cpp …
-Wall: compiler will report all warnings
-std=c++17: the code will be compiled using the C++17 standard
-g: the executable file will contain debugging symbols, allowing valgrind to create better reports -o ws: the compiled application will be named ws
After compiling and testing your code, run your program as following to check for possible memory leaks (assuming your executable name is ws):
bash valgrind ws
To check the output, use a program that can compare text files. Search online for such a program for your platform, or use diff available on matrix.
Car Ads
This application records Car Ads made by different sellers and calculates the price with according to the current tax rate and the special promotions on certain cars.
The application loads the ads information from multiple Ad files. Each file read represents an advertisement from one seller.
Part 1 (0%)
This workshop consists of two modules: – w1 (partially supplied) – carads
w1 Module (partially supplied)
Study the code supplied and make sure you understand it.
Finish the implementation of the main function, by completing the parts marked with TODO:
write the prototype of the main function to receive a set of standard command line arguments
Do not modify this module in any other place!
carads Module
The carads module have the following main parts:
Global Variables
In namespace sdds, implement a function called listArgs that receives the same parameters as the main function (same types, same order).
In the implementation file, implement this function to echo the set of arguments to standard output in the following format:
“` Command Line:
1: 2: 3: 4: … “`
Class Cars
This module also defines a class named Cars in the namespace sdds that stores some information about a car ad:
a C-style null-terminated string of up to 10 characters including the null byte terminator representing the brand of the car. a C-style null-terminated string of up to 15 characters including the null byte terminator representing the model of the car.
the manufacture year of the car.
the price of the car represented by a double value.
the status of the cars as used or new using a single character (holds N or U) a boolean flag indicating whether or not the car is on promotion discount Hint: use safe state for all data members {}
Public Members
default constructor read(std::istream& is): a modifier.
If the istream is in a good state, this function will attempt to read from the istream and store the information read into current object. The data read in will be in the following format: <Order Tag>,<Car Brand>,<Car Model>,<Year>,<Price>,
<Discount status> where:
<Order Tag> can be N (new car) or U (used car)
<Discount status> can be Y (discount applies) or N (no discount)
If the istream object is not in a good state then this function will do nothing.
display(bool reset): a query that displays to the screen the content of an Cars instance in the following format: COUNTER. Brand | Model | Year |Price w/Tax |Special Price
If no car brand has been stored in the current object, this query should print:
COUNTER. No Car where – COUNTER is a left aligned field of size 2, that holds the number of times that this function has been called (use a local-to-function variable that remains in memory for the lifetime of the program) Do not use global/member variables to store the counter! – Brand is a left aligned field of size 10 that represents the brand of the car. – Model is a left aligned field of size 15 that represents the model of the car. – Year is printed as is (assuming it is 4 field number). – Price w/Tax is a left aligned field of size 12 with 2 decimal point precision that represents the price of the car with tax calculated based on the current tax rate. – Special Price is a right aligned field of size 12 that represents the taxed price of the car current promotion applied on top if the order was a discounted price. If the order isn’t a discounted car, then nothing is printed here.
*If the parameter is true, the counter is reset to the initial value.
char getStatus(): a query that returns if the car is new or used.
Add any other private members that your design requires (without changing the specs above)!
Sample Output
The input files ad1.txt and ad2.txt are already provided; the main module contains a description of the structure for these files.
When the program is started with the command: ws ad1.txt ad2.txt ad3.txt ad4.txt the output should look like the one from the sample_output.txt file.
Test Your Code
To test and demonstrate execution of your program use the same data as shown in the output sample.
Upload your source code to your matrix account. Compile and run your code using the latest version of the g++ compiler (available at /usr/local/gcc/10.2.0/bin/g++) and make sure that everything works properly.
~profname.proflastname/submit 345_w1_p1 and follow the instructions.
This part represents a milestone in completing the workshop and is not marked!
Part 2 (100%)
For this part of the workshop, upgrade your Cars class to accept a car brand in the form of a C-style null-terminated string of any length. Make sure your program doesn’t have memory leaks.
In order to facilitate the changes needed for this part, consider the use of these std::string related functions:
std::getline std::string::c_str std::string::length
Implement the rule-of-3. 🗎 Explain in the reflection why these functions are necessary and in what situation a class must implement them.
Enhance the carads module, by adding the following:
Member Functions – conversion to bool operator that returns true if the car is new, false otherwise.
Global Functions – std::istream& operator>>(std::istream& is, Cars& car): has the same functionality as Cars::read(). void operator>>(const Cars& car1, Cars& car2): copies in the second parameter the content of the first parameter.
Sample Output
When the program is started with the command: ws ad1.txt ad2.txt ad3.txt ad4.txt the output should look like the one from the sample_output.txt file.
Note: files ad1.txt and ad2.txt are missing on purpose.
Reflection
Study your final solution, reread the related parts of the course notes, and make sure that you have understood the concepts covered by this workshop. This should take no less than 30 minutes of your time and the result is suggested to be at least 150 words in length.
Create a text file named reflect.txt that contains your detailed description of the topics that you have learned in completing this workshop and mention any issues that caused you difficulty and how you solved them. Include in your explanation—but do not limit it to—the following points: – the difference between internal and external linkage citing examples from your code – what are static variables and how are they useful in your solution. – the changes that you made in upgrading your Cars class in part 2.
To avoid deductions, refer to code snippets in your solution as examples to support your explanations.
Submission
To test and demonstrate execution of your program use the same data as shown in the output example above.
Upload the source code and the reflection file to your matrix account. Compile and run your code using the latest version of the g++ compiler (available at /usr/local/gcc/10.2.0/bin/g++) and make sure that everything works properly.
~profname.proflastname/submit 345_w1_p2 and follow the instructions.
