CMSI 185: Computer Programming

General Details

Due Date: October 19, 2017 [2017-10-19, Thursday of week 08]

The following guidelines are expected for all homework submissions:

All homework must be typed. Homework which is not typed will be returned ungraded and will be subject to the late homework guidelines as set out on the syllabus page. PLEASE DO NOT scribble something on lined paper and rip it out of your spiral notebook — hanging chads went out with the presidential election in 2000.
I don't care too much about what font you use or how large your margins are; however, you might want to check out a monospaced font for typing code, as it will be easy to see the indentations.
Speaking of indenting, PLEASE DON'T USE TABS TO INDENT YOUR CODE. Tabs can often get interpreted differently by different computers and applications, and could make code that is nicely formatted on your computer look "all over the map" on my computer or printer. USE SPACES INSTEAD. You can set up almost every modern text editor to insert spaces whenever you press the TAB key, or you can simply pound the spacebar.
Work with a partner. This mimics an industry code development model called "pair programming" which is part of the Extreme Programming software development method. Feel free to collaborate in your pairs as much as you want, preferably doing the entire assignment together.
DO NOT share your work between groups. Doing so will count as plagiarism. If you wish to discuss solutions with another group over coffee in the Lair, that's fine as long as it is kept at the conceptual level, but each group needs to turn in its own version of the solutions.
You only need to turn in one copy per group.
If you'd like to use the jsfiddle website to do your programs, that is great. Simply save the program in jsfiddle as a shared fiddle, then copy and embed a link to the fiddle into your homework where the answer goes for that problem. I'll use the link to go to YOUR fiddle and run the code. To save your fiddles you'll need to sign up for an account…

Problems From Chapter 2

Ch 2, #30: Check the following poorly formatted script with JSLint by copying it and pasting it into the JSLint text area, then clicking on the "JSLint" button:
```
      var x=0;var y=1;var sequence=[];
         while(y<1000){sequence.push(y);z=x+y;x=y;y= z;}
      alert (sequence);
                
```
Use JSLint's suggestions to clean up the script. (Also, feel free to experiement with JSLint's checkbox options to see what happens.) Submit only your "cleaned-up" version.
Ch 2, #37: Although this text focuses on JavaScript as a language for scripting web browsers, JavaScript is used to write server-side code as well. Read about server-side JavaScript online and try to install the node.js application (available at http://nodejs.org). Do not worry about writing anything in node for now; instead, experiment with node's shell. How is this shell similar to, and different from, the shell from squarefree.com discussed in this chapter?
pg 31, #2 : Explain the difference between the following output strategies: (1) alert, (2) document.write, and (3) modifying the values of HTML elements.
pg 34, #1 : Rewrite the expression:
```
!x && y || z + 5 * 4 >= 3 == y && z
```
in its fully parenthesized form.
pg 34, #2 : Explain, in English, the meaning of
```
x < y || x < z
```
pg 39, #2 : Is first-guess a legal variable name in JavaScript? Provide reasons for your answer.
pg 39, #3 : What does the script
```
var size = 6; alert( Size );
```
do? (Hint: Pay attention to the case of the letters in the names.) Explain.

Problems From Chapter 3

Ch 3, #6 : Execute the following script in the scriptrunner window:
```
      var celsius = prompt( "Enter a temperature in \u00b0C" );
      var fahrenheit = 1.8 * celsius + 32;
      alert( celsius + "\u00b0C = " + fahrenheit + "\u00b0F" );
                 
```
giving inputs of 0, 37, -40, and 100. Then execute with inputs such as dog, 2e600, 3ffc, and Infinity. For each execution, state whether your observed result made sense to you; if not, state why the result differed from your expectation.
Ch 3, #8 : Evaluate the following expressions:

(a) 5 / 0,
(b) 0 / 0,
(c) Infinity + Infinity,
(d) Infinity - Infinity,
(e) Infinity * Infinity,
(f) Infinity / Infinity,
(g) Math.sqrt( Infinity ).

Do these results make sense? Why or why not?
Ch 3, #12: Repackage the die-rolling web page from this chapter so that the HTML document and the script are in separate files. Make the script output values for two dice, and make the output display the proper dice glyph from the HTML set. Be sure to use the style property to make the dice large enough to see easily.

Algorithm Exercises

Exercise 1: Implement a web page that performs the Russian Peasant Multiplication algorithm. You must have two input boxes for the two numbers, and a button to click for performing the operation. You must also have the output show on the footer of the web page (like we did in class for the document properties list), and you must make the output show all the operation's steps in columns. If you are programming in jsFiddle, you may use the tab character to separate the columns, or alternatively you might want to get fancy and use a table to show your output.

Exercise 2: Implement a web page that contains a representation of a stack. The stack must have ten slots. Show the stack vertically on the page with the top of the stack at the top. Include a text input and a button to cause the input value to be pushed onto the stack; also include a button to cause a pop operation to remove the top element. You must be sure to alert if the stack is empty when popping or full when pushing.

Python Programming Problems

Read chapters one through six in the Python book softcopy (it sounds like a lot, but the chapters are quite short — it's only 35 pages). Feel free to try some or all of the exercises at the ends of the chapters, several of which appear below as part of this homework assignment.