Algorithms and OOD (CSC 207 2014S) : EBoards

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




Upcoming Work

Questions on HW4

How do I test for an exception?

    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?


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


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.


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

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