Algorithms and OOD (CSC 207 2014S) : EBoards

CSC207.01 2014S, Class 13: Some Subtleties: References and Automatic Boxing/Unboxing


Overview

Preliminaries

Admin

Upcoming Work

Questions on HW4

How do I test for an exception?

try
  {
    CodeThatShouldThrowAnException();
    fail("Exception was not thrown"); 
  }
catch (Exception e)
  {
    // Success!
  }

Do we have to support PEMDAS (aka order-of-operations)?

No. I would not expect you to figure out the algorithm on your own.

If we find a way to support PEMDAS (say, on StackOverflow), will we get extra credit?

Maybe.

What operations should we support?

Addition, Subtraction, Multiplication, Division, Negation, Store in register

Can you explain the register/storage elements?

Kind of like the store/recall button, but textual

r0 = 2 * 3
r1 = r0 * r0

Do we have to support multiple assignments on one line, as in the following?

r0 = r1 = r2 = 2

No.

Do we have to worry about the calculator equals, which means print?

No. The = is just assignment. Print the value after each line

If you had to write a hash code for fractions, what would you do?

return this.num.hashCode * prime1 + this.denom.hashCode * prime2;

Questions on the Readings for Today

Why won't the following work?

obj = new Integer((obj.intValue())++);

It's similar to writing 5++. You increment variables, not values.

Some More Notes on Exceptions

Some lessons from the Exceptions lab.

Lab

Copyright (c) 2013-14 Samuel A. Rebelsky.

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