CSE 333 Exercise 6

• Write your first C++ class – data members, methods, and access specifiers.
• Examine the effects of pass-by-value and pass-by-reference in C++ on function arguments and return values.
• Define the behavior of standard operators for a user-defined class.

A major addition in C++ compared to C is the introduction of classes! However, there are lots of new stylistic considerations to properly encapsulate these classes, including:

• Const and non-const variables, parameters, and return values,
• Reference vs. non-reference parameters and return values,
• The presence or absence of constructors, destructors, and operators, and
• Member vs. non-member functions. [saved for Exercise 7]

In this exercise, we will put most of these pieces together while writing your first C++ class; carefully consider why each of these different pieces is important!

Create and test a C++ class Vector that implements 3-D vectors in the following two files:

• Vector.h: A header file that declares a class Vector with the following properties:
  • The representation of a Vector should be three floats giving the magnitudes in the x, y, and z directions.
  • The following constructors should be present:
    1. a default (i.e., 0-argument) constructor that initializes a Vector to (0,0,0),
    2. a constructor with 3 floats as parameters giving initial values for the x, y, and z magnitudes (in that order), and
    3. a copy constructor.
  • There should be a destructor that does whatever work is needed when a Vector object is deleted. If no work is needed, the body of the destructor can be empty.
  • The class should define assignment on vectors (u = v).
  • The class should define getters get_x, get_y and get_z that return the corresponding values.
  • The class should define updating assignments on vectors (u += v and u -= v) that perform element-by-element addition or subtraction of the Vector components.
  • Operator * should compute the inner product (i.e., the dot product) of two Vectors as a float. If v1 = (a,b,c) and v2 = (d,e,f), then v1 * v2 should return the scalar value a*d + b*e + c*f.
• Vector.cc: A file containing the implementation of the Vector class.

In addition, you should create the following two files for testing and compiling your Vector class:

• Makefile: The command make should compile the source files as needed to create an executable program named ex6. The command make clean should remove the ex6 executable file, all .o files, and any editor or other backup files whose names end in ~ (e.g., ex6.cc~).
• ex6.cc: A file containing a main function that tests the Vector object. There are two types of tests you should do in this file:
  1. Tests that verify the correct behavior of the defined constructors and operators of your Vector class. For this part of the tests, make sure you utilize the status code to perform proper automated testing as you did in Exercise 3.
  2. After testing the behavior of the constructors and operators, test the behavior of how objects and references are passed in C++. To do this, create two additional functions:
     • Increment(), which accepts an instance of a Vector (not a pointer or reference to a Vector) as an argument, and increments the values stored in the vector by one.
     • VerifyAddress(), which accepts a Vector reference and a void* as arguments, and returns true if the address of the aliased Vector has the same numeric value as the passed-in void*. It should return false if they are not the same integral value.

     For these tests, you should create an instance of Vector and then:

     1. Call Increment() to determine whether the Vector object itself was passed by value or passed by reference to Increment() (i.e., your code should make this determination based on the result of the call; don't hard-code the output).
        1. If it was passed by value, print out on a new line:

           Vector: pass-by-value

        2. If it was passed by reference, print out on a new line:

           Vector: pass-by-reference

     2. Call VerifyAddress() to determine whether the main() instance of Vector is the same instance as the one visible to VerifyAddress by comparing their addresses.
        1. If they are the same (i.e., VerifyAddress returned true), print out on a new line:

           Ref: same address

        2. If false is returned, print out on a new line:

           Ref: different address

     Note that neither Increment() nor VerifyAddress() should print the tests results; they should be printed from main as the last two lines of your output.

$ ./test_ex6
Test cases purposely not revealed.
0 failed

Classes

This is your first exercise with classes, and you should be sure you are following the best standards with commenting and organizing your classes as laid out in lecture. Make sure that you have comments with their declaration in the header file, and have an overall comment describing the behavior of theVectorclass.

Const

Functions, parameters, and variables should be labeled with const appropriately throughout your program. Refer to the lecture material for best practices.

Submit the following file(s) by creating an ex6-submit tag in your repo before the assignment deadline. The file(s) should be located in the exact directory listed below, including capitalization:

• ex6/Vector.h
• ex6/Vector.cc
• ex6/ex6.cc
• ex6/Makefile

For full credit, your code must:

• Compile without errors or warnings on CSE Linux machines (lab workstations, attu, or CSE home VM).
• Have no runtime errors, memory leaks, or memory errors (g++ and valgrind).
• Be contained in the files listed above with your Makefile compiling your code with the g++ options -Wall -g -std=c++17.
• Have a comment at the top of your .cc and .h files with your name(s) and CSE or UW email address(es).
• Be pretty: the formatting, modularization, variable and function names, commenting, and so on should be consistent with class style guidelines. Additionally, the linter shouldn't have any complaints about your code (cpplint.py).
• Be robust: your code should deal with hard-to-handle/edge cases and bogus user input (if there are any) gracefully.