This assignment has some reading, a number of administrative tasks and a warm-up problem on Objective C. The reading and administrative tasks are due by classtime Thursday. The warm-up programming project is due by next Friday January 27 at 5PM.

Reading and Administrative Tasks (Due by classtime Thursday)

1. Read About iOS Development and read Chapters 1 and 2 of MNL.

2. If you aren't already a member, visit Apple's iOS Development Center and register for the iOS Developer Program.

3. If you haven't already done so, download and install Xcode.

4. Send me an email answering the following questions:
   1. What year are you and what is your major?
   2. What CS courses have you taken?
   3. Have you done any iOS programming? If so, how many months of experience?
   4. What programming languages do you know? For each, how well do you know the language (out of 10 with 10 being expert).
   5. Do you own a Mac? If so, what kind and what version of Mac OS X are you running?
   6. Do you own an iPhone? Do you own an iPad?
   7. What is the air-speed velocity of an unladen swallow?
   8. Do you have a app project in mind? If so, please briefly describe it. (If not, start thinking about it!)

Implementing a Reverse Polish Notation (RPN) Calculator (Due 5PM, 1/27/2012)

The first demo from class as well as this first problem set are both adapted from material presented in the 2011 edition of Paul Hegartys' CS193P iPad and iPhone Application Development course at Stanford. It's an excellent course and I highly recommend the materials. This problem set isn't identical to CS193P problem set 1, but it's pretty close --- an RPN Calculator makes a great starter problem for touch sensitive platforms in general and iOS in particular. Reverse Polish Notation Fully parenthesized arithmetic expressions can be evaluated by a method called reduction and rewriting. The idea is as simple as it is familiar: evaluate the subexpressions from left-to-right until the value of the entire expression is obtained. For example, pronouncing "-->" as "rewrites to", we could evaluate the expression (2 + 3) * (4 - 1) as follows: ((2 + 3) - (2 * 2)) --> (5 - (2 * 2)) --> (5 - 4) --> 1 The explicit parenthesization determines the order in which the operation will be carried out. In the absence of parentheses, we rely on rules governing the precedence and associativity of the operators, they cannot simply be evaluated left-to-right. (Try it, on 2 + 3 - 2 * 2.)

2 3 + 2 2 * - -->
5 2 2 * - -->
5 4 - -->
1

Examining the above evaluation sequence, we see in the second line that when we scan rightward to find the multiplication operator *, we are effectively using the notation on the left as a stack of operands. In particular, when we find an operator, we pop the most recent 2 operands off the stack, combine them with the operator and then push the result back on the stack and continue scanning. This is the basis of the RPN calculator that we developed in class.

In the demo code from class, we implemented code that would accept interaction of the form: number, Enter, number Enter, operator. In this problem set you are to expand the calculator by adding:

1. A . (dot) button --- this button will allow the user to enter floating point numbers. Note that a floating point number has at most 1 dot!

2. A Clear button --- this button should cause erase the display;

3. A sqrt button --- this button should compute the square root of the value on top of the stack;

4. A pi button --- this button should push the floating point number 3.14 onto the stack.