CMSC 202 Fall 2006
Homework 2

Overloaded Operators

Assigned Sunday October 22, 2006
Program Due Sunday October 29, 2006 at 11:59pm
Updates

Objectives

Description

One of the tools you can use within C++ is that of overloading operators. This is a highly controversial tool in the Object-Oriented community as some believe it is a dangerous tool while others believe it allows a developer to use built-in constructs in a reasonable manner. One of the most common examples of the usefulness of overloading operators is a three-dimensional vector class. 3D games use these basic vectors as the fundamental basis for all polygon representations.

Assignment

You have been tasked with the responsibility of developing a 3D vector class to be used in your company's application software.

3D Vector Class

A 3D Vector has three coordinates (x, y, z). Each coordinate is a double precision number. A default 3D Vector has zero for all three dimensions (0.0, 0.0, 0.0). Vectors must be displayed with 1 decimal of precision in a fixed format.

The design of the class is left up to you, however, you must:

Application Functionality

Your application must begin with a legend that instructs the user what the purpose of the application is for and how to use it.

Your application must support the following menu of choices and corresponding actions, with the following integers used to select each:

Input/Output Format Guarantees

  • All 3D vectors are formatted (both printed and received from the user) as follows: (x, y, z)
  • All 3D vectors have 3 dimensions represented by double-precision values
  • All double-precision values must be displayed with exactly 1 decimal point of precision: 136.0
  • All numerical values received from the user will be in decimal form
  • All input to the system will be of the correct type and will be an acceptable value

    Negation of a 3D Vector

    The negation of a vector is simply the negation of each of the dimensions: -(1.0, -2.0, 3.0) = (-1.0, 2.0, -3.0)

    Length of a 3D Vector

    The length of a vector is simply the square root of the sum of the square of each dimension. The length is simply: length(a1, a2, a3) = square_root(a1^2 + a2^2 + a3^2) (Note: the above formula is not valid C++)

    Addition of two 3D Vectors

    The addition of two vectors is simply the sum of each dimension: (1.0, 2.0, 3.0) + (0.5, 2.4, 5.1) = (1.0 + 0.5, 2.0 + 2.4, 3.0 + 5.1) = (1.5, 4.4, 8.1)

    Subtraction of two 3D Vectors

    The subtraction of two vectors is simply the difference of each dimension: (1.0, 2.0, 3.0) - (0.5, 2.4, 5.1) = (1.0 - 0.5, 2.0 - 2.4, 3.0 - 5.1) = (0.5, -0.4, -2.1)

    Dot Product of two 3D Vectors

    The dot product is a scalar (double-precision) value correlates to the cosine of the angle between the two vectors. The dot product is computed as follows: (a1, a2, a3) . (b1, b2, b3) = a1 * b1 + a2 * b2 + a3 * b3

    Cross Product of two 3D Vectors

    The cross product is a vector that is perpendicular to both of the given vectors. The cross product is computed as follows: (a1, a2, a3) x (b1, b2, b3) = (a2 * b3 - a3 * b2, a3 * b1 - a1 * b3, a1 * b2 - a2 * b1)

    Files

    You can copy all necessary files from the following directory: /afs/umbc.edu/users/d/a/dana3/pub/CMSC202/hw2/

    makefile

    The makefile supplied will allow you to build and test your application. You will need to alter the makefile to support your 3D Vector class. A macro has been created to simplify this - in the makefile, look for 'VECTOR', and change the right-hand side to be the name of your Vector class.

    You can use make test to run your application on the supplied input file. The output should match the example output EXACTLY. You can use diff exampleOutput.txt output.txt to verify that the files are the same. If nothing prints to the screen, then the output is identical, otherwise, there are some differences.

    input.txt

    This is an example of the input file that your application must work with. It is NOT a comprehensive testing suite - you should develop your own testing suite to test your class, but you can use this file as a starting point.

    exampleOutput.txt

    This is an example of the output that should be produced by your program when run on input.txt.

    Grading

    The grade for this homework will be broken down as follows. A more detailed breakdown will be provided in the grade form you receive with your homework grade.

    85% - Correctness and Design

    This list may not be comprehensive, but everything on this list will be verified by the graders.

    15% - Style and Standards

    Your code must adhere to the course coding standards.

    Homework Submission

    What to Submit

    You must submit the following files:

    Steps for Submission

    1. submit all files
    2. submitls to verify they are in the remote directory
    3. submitmake to build your files remotely
    4. submitrun to run the application in your remote directory
    Assuming you've used the recommended file names, then to submit your homework, type the command submit cs202 Hw2 files ... The order in which the files are listed doesn't matter. However, you must make sure that all files necessary to compile your project (using the makefile) are listed. You need not submit all files at the same time. You may resubmit your files as often as you like, but only the last submittal will be graded and will be used to determine if your project is late. For more information, see the projects page on the course website.

    You can check to see what files you have submitted by typing

    submitls cs202 Hw2

    Be sure to build your project once it has been submitted using the submitmake command, so that you know that all of the files are there and are the most up-to-date versions:

    /afs/umbc.edu/users/d/a/dana3/pub/CMSC202/submitmake cs202 Hw2

    More complete documentation for submit and related commands can be found here.

    Remember -- if you make any change to your program, no matter how insignificant it may seem, you should recompile and retest your program before submitting it. Even the smallest typo can cause compiler errors and a reduction in your grade.

    Avoid unpleasant surprises!

    Be sure to use the submitmake utilities provided for you to compile, link and run your program after you've submitted it.