Program #4 Designing Your Own Calculator

Program #4
 Points 100
Designing Your Own Calculator
Introducon
For this homework project you will have two weeks to complete the programming portion of the assignment.
However, you will be required to submit a design document to Canvas (due on Sunday, October 28th,
11:59pm). You can use the same documentation template and format that was introduced during week 2.
Please review the recitation syllabus
(https://web.engr.oregonstate.edu/~goinsj/resources/CS161/CS161_Recitation_Syllabus.pdf) (available from the
Recitations tab) for additional details on the design document expectations.
Example design document (introduced in week 2): Polya_template.pdf
(https://web.engr.oregonstate.edu/~goinsj/resources/CS161/Polya_template.pdf)
Notice that the design of this program is more open-ended than previous assignments. Oftentimes realworld assignments require the software designer to start from scratch and create a solution. For this
assignment you must design a program that can solve the problem statement and you must then implement
your solution.
(85 points) Problem Statement
There are many calculations that computers can help us with. You are to make a calculator program for this
assignment which will allow users to do standard calculations (+, -, *, /), binary to decimal conversion,
decimal to binary conversion and a grade calculator. The user should have the option to choose which
form of calculation they want to do. At the end of each calculation, the user should be asked if they want to
do another calculation or exit the program.
The standard calculator should be able to handle floats and ints. It should take the equation on one line as a
string.
For an example of the standard calculation:
What is your equation? 5 * -7
Result: -35.
Clarification (10/23/18): Here is an example that illustrates the requirement mentioned below that "...there
should not be competing precedence. Everything will be calculated left to right." In essence, you just have to
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process the operators as you encounter them. This makes the assignment easier, rather than having to
implement the normal mathematical order of operations.
What is your equation? 6 + 4 / -2.5 - 5.25
Result: -9.25
Explanation:
6 + 4 = 10
10 / -2.5 = -4
-4 - 5.25 = -9.25
Addional Requirements
Clarification (10/23/18): Your code should detect cases where the number or ordering of operands is
incorrect. For example, the calculation "6 + 4.125 + 7 9" would display an error, as would "6 + / 6".
There should be spaces between each operand and operator. Clarification (10/24/18): You can assume
that the user will include these spaces (e.g. the TAs will not test the calculator portion of your code with
input strings that don't contain spaces).
There should not be competing precedence. Everything will be calculated left to right.
The binary conversions will only handle unsigned, positive values.
The grade calculator should prompt for the number of grades to be entered, collect those grades from
the user and average them. The user should also be given an option to calculate a weighted average.
For this option the program will need to take a weight from the user and multiply it by the average. If you
are unfamiliar with weighted averages, see the introduction at: https://www.wikihow.com/CalculateWeighted-Average (https://www.wikihow.com/Calculate-Weighted-Average)
Clarification (10/29/18): For the weighted average calculation, it is sufficient for your code to accept a set of
grades and associated weights to be applied.
Example for that part of the program:
You chose to compute a weighted average.
How many entries need to be averaged?
4
Please enter grade #1:
88
Please enter weight #1:
.25
Please enter grade #2:
95.6
Please enter weight #2:
.30
Please enter grade #3:
79w
Oops, invalid input.
Please enter grade #3:
79
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Please enter weight #3:
.15
Please enter grade #4:
91
Please enter weight #4:
.30
The weighted average is: 89.83
Your program should handle all input errors such as a user putting in an invalid character or number. e.g.
To get full credit you should detect empty strings and invalid input such as "cat" or "k2.53". Additional
error checking is extra credit (see the helpful hint section).
All function bodies must be 15 lines of code or less, including main(). Whitespace and lines with just curly
braces do not count in the line count.
No global variables or goto functions.
Helpful Hint (10/31/18)
If you have started to work on the calculator code, it quickly becomes apparent that it is extremely difficult to
do a good job validating the user's input line.
For example, each of the following input lines is invalid:
a5.2 + 3
5.2 + 3 /
5.2 * + 3
Due to the difficulty of catching all possible errors, I will add up to 10 points of additional extra credit to
submissions that can properly reject any faulty inputs in the user's input. Remember, your code still needs to
be written with <= 15 lines of code inside each function.
Examples of erroneous input that you need to detect for full credit:
5.4 * 24 + / 25
5.4 * 24 +
27.2 / 6.5 85
b28 * 3.5
2.4 / cat
(empty string)
Examples of erroneous input patterns that you can detect for extra credit:
5.8w + 2.5
23.5 / -7.8-
4.42 - 3..9
I uploaded some example code that illustrates how to catch many of these errors.
I suggest opening this file in a text editor that has syntax highlighting to make it easier to read.
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It's available online
at: https://web.engr.oregonstate.edu/~goinsj/resources/CS161/demos/calculator_parsing.cpp
(https://web.engr.oregonstate.edu/~goinsj/resources/CS161/demos/calculator_parsing.cpp)
You are completely welcome to incorporate my example C++ code into your program as you see fit.
(15 pts) Program Style/Comments
In your implementation, make sure that you include a program header in your program, in addition to proper
indentation/spacing and other comments! Below is an example header to include. Make sure you review the
style guidelines for this class
(https://web.engr.oregonstate.edu/~goinsj/resources/general/cpp_style_guideline.pdf) , and try to follow them,
i.e. don’t align everything on the left or put everything on one line!
/******************************************************
** Program: calculator.cpp
** Author: Your Name
** Date: 10/25/2018
** Description:
** Input:
** Output:
******************************************************/
Don't forget that each of your functions needs to have a header. For example:
/******************************************************
** Function:
** Description:
** Parameters:
** Pre-Conditions:
** Post-Conditions:
******************************************************/
(10 pts) Extra Credit
Submit an updated, annotated version of your design. How did your design change between when you
submitted for recitation and when you submit for your assignment? Make sure to complete your testing
table.
(10 pts) Extra Credit (added 10/24/18)
If you are looking for an additional challenge, write your code so that it can decode and correctly interpret
parenthesis to indicate the preferred order of operations
For example:
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Program #4 Rubric
What is your equation? ( 6 + ( 4 / -2.5 ) ) - 5.25
Result: -0.85
Assignment Submission
Note that there are two deadlines for this assignment.
Your design document must be scanned and electronically submitted to Canvas (in the assignment tab) by
Sunday, October 28th, 11:59pm. You may use one of the document scanners (available in KEC1130 and
some other College of Engineering labs) to scan your paper design into a PDF document that can be
submitted to Canvas.
Electronically submit your C++ source code to TEACH (https://engineering.oregonstate.edu/teach) by the
assignment due date on Sunday, November 4th, 11:59pm. Your TEACH submission should contain the
.cpp file with your source code. If you choose to do the extra credit, you may also include a PDF file with
your annotated program design and a list of the changes made to your design.
Reminder
Every assignment in this course is graded by demoing your work for 10 minutes with a TA. You are required
to meet with a TA within two weeks of the due date to demo. You can schedule a demo with a TA from
the TA Office Hours tab in Canvas. The available times can be viewed in the far right column of the table
(labeled "Grading Hours"). Click on one of the links to access the poll and insert your name in a specific time
slot.
Demo Outside 2 Weeks: Assignments that are not demo'd within the acceptable time period will be
subject to a 50 point deduction.
Demo Late Assignments: Late assignments must still be demoed within the two week demo period
beginning from the assignment's original due date.
Missing a Demo: If you miss your demo with a TA, you will receive a 10 point (one letter grade)
deduction to that assignment for each demo missed.
Each program needs to be written according to the style guidelines
(https://web.engr.oregonstate.edu/~goinsj/resources/general/cpp_style_guideline.pdf) for this class. Remember
that an important part of computer programming is making sure that your work is easily understandable by
other programmers.
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Criteria Ratings Pts
5.0 pts
5.0 pts
5.0 pts
8.0 pts
12.0 pts
8.0 pts
2.0 pts
2.0 pts
2.0 pts
2.0 pts
2.0 pts
2.0 pts
2.0 pts
7.0 pts
4.0 pts
4.0 pts
4.0 pts
4.0 pts
2.0 pts
Program Header
At a minimum, header should contain author's name and a description of the program. (2 pts
each) 1 point for submitting code that compiles on flip.
Good indentation / Use of whitespace
Is code easy for the TA to read? Conditional blocks of code should always be indented.
Each function is documented
Every function contains it's own initial block comment (or multiple lines of comments prior to the
function definition) that provides the reader with an explanation of the function's purpose. -1 pt for
each function that is missing a header
User has the option to select standard calculator, binary to decimal, decimal to binary, and grade
calculator (2 pts each)
All function bodies are <15 lines (excluding lines with just curly braces and lines with only
comments). -3 points for each function over the limit
All parts of the program handle error checking for the following input: <blank line "cat" "." -2 pts
for each section of code that doesn't reject all of those inputs
User's calculator detects invalid input for: 10 10 +
User's calculator detects invalid input for: 10 + *
User's calculator detects invalid input for: + 10 10
Calculator correctly computes 10 for: 2.4 + 7.6
Calculator correctly computes -5.2 for: 2.4 - 7.6
Calculator correctly computes 19 for: 2.5 * 7.6
Calculator correctly computes 8.25 for: 41.25 / 5
Calculator correctly computes 39.5 for: 50 / 5 * 7 - 25 + -5.5
Binary to decimal calculator correctly converts 101010 into 42
Binary to decimal calculator correctly converts 1001001 into 73
Student's code correctly converts decimal 73 to binary: 1001001 (extra leading 0's are okay)
Student's code correctly converts decimal 61680 to binary: 1111000011110000 (extra leading 0's
are okay)
User can choose to run grade calculator mode (average & weighted average)
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Total Points: 100.0
Criteria Ratings Pts
4.0 pts
3.0 pts
4.0 pts
4.0 pts
3.0 pts
0.0 pts
0.0 pts
0.0 pts
Grade calculator code prompts for number of entries (and uses the value correctly)
Student's code correctly calculates average of 3 numbers
Student's code correctly computes weighted average of 3 inputs
No global variables or goto functions anywhere (these points are all-or-nothing)
User can choose to repeat the program after each calculation
Extra credit (10 pts): The calculator rejects the following input (2.5 pts each): "12 + 34w" "2.3. * 4"
"5 * -7.7-" "3 / -23.j"
Extra credit (10 pts): The standard calculator can process parenthesis to indicate the preferred
order of operations. 4.5 - (9.0 / 3) should display 1.5
Note that the recitation TAs will grade the 10 pts of extra credit for submitting an updated,
annotated version of your design documents. This will not be checked during the demo.