Assignment #1 Grading Summary

Programs with incorrect or no output received a grade between 20 and 40.

Items in boldface were common.

Items are listed in the order that they were seen as I graded the assignments.

DEDUCTION	PROBLEM	COMMENT
-2	if( cond ) return true; else return false;	Should be: return cond;
-15	Consistently not checking for emptiness in find and delete operations
-3	One-time not checking for emptiness in find and delete operations
-7	Catching the exception in find and delete operations	Should let it propagate back to caller.
-10	Consistently creating extra arrays, especially in deleteMax
-3	One-time creation of unneeded extra array
-2	Underflow constructor not made public
-10	Insufficient Javadoc comments
-6	Javadoc comments attempted, but in wrong place	Prior to the method, rather than in the method
-10	Complicated logic	Each method should fit easily in 60 lines.
-3	Consistently inconsistent spacing. For instance, one loop looks like a[i ] = a[ i+1 ]; Another looks like a[ i]= a[ i + 1 ];	Pick one style and stick with it.
-10	Indenting disaster
-5	Indenting problem
-3	One time indenting problem that was really misleading to the reader
-7	Horrible variable names
-3	Using o or l as a variable name	Avoid because they look like 0 and 1.
-2	Missing else, as in if( x < 0 ) { … } if( x >= 0 ) { … }	Rewrite as if/else.
-5	makeEmpty doubling inconsistency	If you (exactly) doubled the array, then you could not have makeEmpty resize the array to length 0, without creating a bug.
-3	Putting an isEmpty test too late (i.e. after indexing the array).	The test had to be the first line of code.
-15	Messing up the default comparator completely.
-5	Having the default comparator return 0 if one type is not Comparable.	Should let the ClassCastException that is generated go through.
-5	UnderflowException extends the wrong class.	Must extend RuntimeException.
-3	Gratuitious calls to create objects, as in Object temp = new Object();	Should have been Object temp = null;
-2	Nonsense code; for instance random calls that ignore return values.
-15	Nested loops in the insert routine, or doing a full sort.	You should not have needed to nest loops. Generally lost points unless there was a comment or an early break from the outer loop.
-5	Declaring extra instance variables instead of local variables.
-5	Print statement in the exception constructor.	Contructor shouldn’t do anything, except call super.
-2	Using a while loop instead of an obvious for loop.
-5	Constructing an exception object but not throwing it.
-5	Having toString print the size, but not the items.
-5	makeEmpty throws an exception if already empty.	This is an unreasonable design decision. There is nothing usual about clearing a container that is already cleared. It is similar to initializing to 0 a variable that is already 0.
-8	One parameter constructor that accepts a Comparator messed up.
-2	Writing an else if, when an else was enough as in: if( x < 0 ) { … } else if( x >= 0 ) { … }	Rewrite as if/else.
-11	Test for emptiness, but no attempt to create or throw the exception.
-3	Using System.arrayCopy when not needed, which often involved creation of a temporary array.
-0	Using size==0 instead of calling isEmpty.
-5	Abusive use of ++ operator, as in a[i] = a[++i];
-1	Keeping capacity as a separate member	Already stored as array length.
-3	No space in toString to separate the items output, resulting in one giant string with no blanks.
-1	Placing throws RuntimeException in the signature of a method. This is meaningless.
-5	Having isEmpty work by testing items[0]==null might not work, depending on implementation of deleteMin and deleteMax. If it didn’t work, points were deducted.
-5	Catching ArrayIndexOutOfBoundsException to decide when it is time to expand the array.	This is a big no-no. The test should be done explicitly, and exceptions should not be used as a substitute for if/else.
-15	findMin/deleteMin didn’t simply look in position 0, but searched the entire array.
F for course	Cheating.