*** Official AP Computer Science A Thread 2013-2014 ***

<p>Everyone’s saying that they thought the multiple choice was unusually hard. I didn’t think it was too much harder than the Barron’s MC. What are some of the questions you guys found difficult?</p>

<p>Do you guys think 55/80 will make a 5? I think I aced FRQ but bombed MC, not sure how badly but pretty badly…</p>

<p>I didn’t find the MC hard as much as I felt that there were way more code run throughs than Barron’s test had, which changed how long it took me to finish.</p>

<p>@Cornball‌ yes that was the case with most of us. Hopefully the curve will justify that. I calculated that if one does near perfect on the FRQs, they can get almost 17 questions wrong on MC</p>

<p>yeah I agree. I didn’t think the multiple choice was that hard, there was like 1 question that I had a little trouble with(unsurprisingly it was in the gridworld part) but it was so long and tedious. I only checked over like half the answers so I hope I didn’t make any silly mistakes. </p>

<p>I thought the MC was much more easier than the FRQs. I think I got about ~35 on the MC.</p>

<p>On the FRQs however, I kind of made some dumb mistakes.</p>

<ol>
<li>(a). I really wrote like nothing. I wrote a for-each loop to check the values in the arraylist. Then I set the subtring(i, i+1) = substring(i+1, i+2) and just returned that.wrote an if statement to check if the first letter was A and the second letter wasn’t A. Most likley -2/-3 points on that portion.</li>
</ol>

<p>(b). I used a for-each loop (horrible mistake) to check through the arraylist and then I assumed my method in part a would work so I created a news string that was the parameter’s string scrambled. Then, through the for loop, I checked the values and added the scrambled word if it wasn’t there. However, if it wasn’t, I used the arraylist name.remove(object);, which actaully returns an exception, which I didn’t know (Link: <a href=“Calling remove in foreach loop in Java - Stack Overflow”>Calling remove in foreach loop in Java - Stack Overflow). I’m thinking I would get only 1 point off, since my code worked but only returned an exception b/c it was a for-each loop and not a for loop.</p>

<ol>
<li><p>This was incredibly easy. However, when I created a void method called turn to make the actors turn, and when I used the loop (Actor a: actors), I accidentally put turn(); instead of a.turn();. Most likely I’ll get 1 point off for it.</p></li>
<li><p>(a). Forget some things here. First, I forget to initialize the array, and then I also forget to counter the loop with the arraylist size, leading to an outofbounds exception error. -2 points for this.</p></li>
</ol>

<p>(b). I forget to check whether the [row][col] was null or not. -1 point of for this.</p>

<ol>
<li>I think I did this one perfectly. For the getPrice() method, I created a <double> arraylist and casted all the double primitive types to Double objects (this works, you can look it up, it is called autoboxing). Then, I searched through the arraylist, find the minimum value and used remove(object) to remove the object. I then return the sum of the 2 other values.</double></li>
</ol>

<p><em>NOTE</em> remove(object) is an actual method. Only when used in a for-each loop, can it cause an exception error.</p>

<p>Most likely my earning on the exam.</p>

<p>MC: 35</p>

<p>Q1: 5/6</p>

<p>Q2: 8</p>

<p>Q3: 6</p>

<p>Q4: 9</p>

<p>which, rounds off to a mid-5.</p>

<p>If anyone can tell me whether or not my scoring guidelines for my FRQs are legitimate or not, that would be great. To most of you, it may look as if I used a very far-fetched method, but as long as the code works, I don’t see why I would get marked down. These are the solutions I saw with the FRQs.</p>

<p>Thanks in advance to anyone is they can give me some feedback on my scoring. </p>

<p>Does anyone know when the multiple choice questions will be released?</p>

<p>Multiple choice questions are never released. CollegeBoard re-uses some of the multiple choice questions from year to year, in order to help it know where to set the grade cutoffs each year. This is one of the reasons why students are forbidden from discussing the content of the multiple choice questions.</p>

<p>(Well, almost never. Roughly every 5 years or so, CollegeBoard will publish an entire exam for sale to instructors to use in their courses. Obviously, at that point, it won’t re-use questions from published exams.)</p>

<p>@Vigilante13‌ </p>

<p>I made the same exact mistake you did on 1 a)</p>

<p>So, are my grading scales okay, in the sense that the AP graders will most likely give me these scores. I really want a 5; I kind of failed on the FRQs but at the same time think I had enough code to at least get partial credit. I’ve heard from others that the graders are also really really generous. If anyone objects to my grading scale, please, tell me now and what you think I would most likely receive. Good luck to everyone.</p>

<p>Also, for FRQ #2, are you allowed to say: if(getColor() == Color.RED) { //code here }. I used that. Would I get points off for this or would the graders be generous and give me benefit of doubt?</p>

<p>@Vigilante13 It’s really hard to say if your scoring scheme is correct without designing the entire grading rubric for all four problems.</p>

<p>For FRQ 2: You might be okay, depending on how the rest of the code works. If your solution only ever uses two color objects, Color.RED and Color.GREEN, you might be okay, since then you really only need reference equality to check which of the two objects you’re considering. But that’s one of the questions that will have to get worked out during the scoring session.</p>

<p>For the second FRQ I put get.Direction() + RIGHT instead of Location.RIGHT you think they’ll take a couple points for that or no?</p>

<p>@jkhuggins okay thanks for the feedback. I only used Color.GREEN and Color.RED, so most likely I won’t get points off. The rest of my code was exactly as other solutions have posted it, so it works fine. If anything, I would only get off because I said turn(); instead of a.turn();.</p>

<p>I also understand that my grading scheme doesn’t entirely cover every aspect of all the questions. I’ve assumed that the points I’ll receive will be given, so again, hope i get a 5 on this exam. </p>

<p>I think RIGHT instead of Location.RIGHT will probably lose the corresponding point for correctly computing the turn.</p>

<p>just putting in a.setDirection(a.getDirection()+90) works too right?</p>

<p>Yep, pretty sure that works too. In the past, GridWorld solutions haven’t required the use of the literal constants.</p>

<p>Hello, I am doing the late-testing on Thursday and I just had a small doubt.
If we instantiate an object </p>

<p>Shape a = new Circle (parameters);
Shape s = null;
s = a;</p>

<p>And if the method getRadius( ) only exists for circles but not for shapes (btw Circle class extends Shapes class) would the statement s.getRadius ( ) execute without an error. Thanx</p>

<p>@shijurodhaz‌, the method wouldn’t compile. You’re creating a shape object. Therefore, because the method is only found in the circle class, you wouldn’t be able to access it.</p>

<p>@Vigilante13‌ Thanx…one more question if Shape implements Comparable can we say that Shape is-a Comparable. So if Shape s= new Shape (parameters) do we have to use a cast to change s to a Comparable or can we just write Comparable s.</p>