CS140 -- Midterm Exam: Grading

Just one comment -- I do give partial credit for certain answers below. If you did get partial credit, you should know that your answer was wrong, but enough of your thinking was right to warrant some points. If you did not get partial credit for an answer, do not come and try to argue with me and explain your thinking -- my answer will be that you got the problem wrong and you were not thinking along the lines that I wanted you to think along.

The multiple choice grading is kind of detailed -- it was done automtically, obviously with a program that you are capable of writing. If you'd like to see it (of course, it uses the fields library), it is in grader.c. Try it out if you want.

Questions 1-3

Questions 1 through 3 were worth three points each. Grading was as follows:

Question 1: 3 points for c. Zero points for anything else.
Question 2: 3 points for i. I gave one point for g, d, and j, which meant that you made one small, reasonable mistake.
Question 3: 3 points for c, and one point for f, which happened when you thought that a() modified i and j. Also, if you missed question 1, but gave the same answer for questions 1 and 3, then I gave you 1 point, because you at least understood that a() did not modify i and j.

Questions 4-7

Questions 4 through 7 were worth four points each. Grading was as follows:

Question 4: 4 points for b. Zero points for anything else.
Question 5: 4 points for d. Zero points for anything else.
Question 6: 4 points for d. One point for b, which I took as meaning that you thought that s and s1 pointed to different places (i.e. "s = strdup(revstring(s1));").
Question 7: 4 points for h, 3 points for j, 1 point for c, which is what you would get if there were actually memory allocated for s.

Questions 8-11

Questions 8 through 11 were worth four points each. Grading was as follows:

Question 8: 4 points for g, and one point for h, which means that you messed up the (i+1) in line 2.
Question 9: 4 points for l, three points for m, meaning you had the value of i wrong, and one point for h, meaning you missed the error, but got the math right.
Question 10: 4 points for k, three points for l, meaning you had the value of i wrong, and one point for h, meaning you missed the error, but got the math right.
Question 11: 4 points for e, three points for d, meaning you spaced on the last line, and one point for k, meaning you though line two was an error since it had no words on it.

Questions 12-14

Question 12 was 4 points. Questions 13 and 14 were 5 points each. Grading was as follows:

Question 12: You received 4 points for answering b. If you answered b and any other answer, but you didn't circle c, you got 2 points. If you answered b and c (and/or any others), you got 1 point. If you did not answer b, you received zero points.
Question 13: If you answered just c and e, you received 5 points. If you answered c or >e only, received 4 points. If you answered c and/or e and also put down other things, you started with the points above, and were penalized in the following way:
- 1 point off for answering b and/or f, because at least their types are all correct -- they are just missing memory allocation.
- 2 points off for answering a, d and/or g.
If you didn't answer c or e, then you received one point for ansewring b or f, but not the others. Zero otherwise.
Question 14: If you answered just c and g, or c, g and d, you received 5 points. If you answered c only g only, c and d or g and d, you received 4 points. If you answered d only, then you received 3 points. If you answered c d and/or g and also put down other things, you started with the points above, and were penalized in the following way:
- 1 point off for answering e, h and/or f, because they aren't quite as bad as the others.
- 2 points off for answering a and/or b.
If you didn't answer c, d or g, then you received one point for ansewring e, h or f, but not the others. Zero otherwise.

Question 15

Question 15 was worth 10 points, allocated as follows:

Getting the main(int argc, char **argv) declaration right: 2 points.
Getting the for() loop right: 3 points. If you had the indices wrong, you lost a point.
Doing a printf("%c", ... or a putchar(): 1 point.
Actually finding and printing the right character: 4 points.

Question 16

Question 16 was worth 25 points, allocated as follows:

Declarations: 3 points
- Having a FILE *: 1/2 point.
- Having an int for n: 1/2 point.
- Having an array for the lines: 1 point. Only 1/2 point if you got the type wrong.
- Having a IS, or a big character array for input: 1/2 point.
- Having an induction variable for the for/while loop: 1/2 point.
Error checking for the right number of argument: 1 point.
Getting that error checking right and printing out the right thing: 1 point.
Setting n with atoi() or ssanf(): 2 points.
Error checking n: 1 point.
Getting that error checking right and printing out the right thing: 1 point.
Doing the fopen(): 1 point.
Error checking the output of fopen(): 1 point.
malloc()-ing an array for the lines: 1 point.
Making sure you have n elements in that malloc(): 1 point.
Getting the types and sizeof() in the malloc() right: 2 points.
Initializing the IS (you get this point for free if you used gets()): 1 point.
Having a loop to read input: 1 point.
Having the loop end on EOF or n lines: 2 point. If you only had it end on one of these conditions, you lost a point.
Calling strdup(): 2 points.
Having a loop to write the output: 1 point.
Having the right variables in that loop so that the lines get printed backwards: 1 point.
Getting the fprintf() or fputs right: 1 point.