Spring Semester 10 Exam #1 Dr. Dillon. (02/18)

Transcription

1 Spring Semester 10 Exam #1 Dr. Dillon. (02/18) Form 1 B Last name (printed): First name (printed): Directions: a) DO NOT OPEN YOUR EXAM BOOKLET UNTIL YOU HAVE BEEN TOLD TO BEGIN. b) You have 80 minutes to complete the exam (12:40 2:00 pm) c) This exam booklet contains 26 multiple choice questions, each weighted equally (5 points) and one 20 point programming problem. (27 questions, 9 total pages) d) You may also use one 8.5" x 11" note sheet during the exam. No other reference materials or electronic devices may be used during the examination. e) Questions will not be interpreted during the examination. f) You should choose the single best alternative for each question, even if you believe that a question has multiple correct answers, is ambiguous or contains a typographic error. g) Fill in the requested information at the top of this exam booklet. h) Use a #2 pencil to encode information on the OMR form. i) Encode the following on the OMR form: Last name and first initial MSU PID Exam form (see the top right corner of this page) j) Sign the OMR form. k) Only answers recorded on your OMR form will be counted for credit for multiplechoice questions. l) Completely erase any responses on the OMR form that you wish to delete. m) You must turn in this exam booklet, your cheat sheet, your scratch paper, and the OMR form when you have completed the exam. (All will be returned to you in your section meeting after the exams are graded.) n) When leaving, please be courteous to those still taking the exam. Good luck! Timing tip. A rate of 2.5 minutes per multiple choice problem leaves 15 minutes to write the program (worth 20 points) at the end Form B B B C C A D B D CD B C B A B D C D D D E B D C B B D

2 Figure 1 1) In Figure 1, what is printed by Line A if the user enters 1 at the prompt? a) s = -1 b) s = 1 c) s = 0 d) Line A is not executed. 2) In Figure 1, what is printed by Line B if the user enters 1 at the prompt? a) t = 0 b) t = -1 c) t = 1 d) Line B is not executed. 3) In Figure 1, what is printed by Line A if the user enters 3 at the prompt? a) s = -1 b) s = -2 c) s = 2 d) Line A is not executed. 4) In Figure 1, what is printed by Line B if the user enters 3 at the prompt? a) t = 0 b) t = 2 c) t = 4 d) Line B is not executed. 5) In Figure 1, what is printed by Line C if the user enters 3 at the prompt? a) 3 b) 1 c) 0 d) Line C is not executed.

3 6) In Figure 1, what is printed by Line C if the user enters 0 at the prompt? a) 0 b) 1 c) 3 d) Line C is not executed. 7) In Figure 1, what type does the variable numstr have when Line C is executed? a) integer (int) b) string (str) c) float d) character (char) 8) What value is returned by the expression len(range(-100,100))? a) 99 b) 100 c) 199 d) 200 9) Which of the statements about the value of range(1000) is incorrect? a) It is a list. b) It may appear in the head of an if statement c) It contains a syntax error. d) It is immutable e) None of the above (i.e., all of the above are correct). 10) Which of the statements about the following Python command is incorrect? >>> A = (B < C) a) It does not return a value. b) It produces a syntax error. c) It produces an exception (execution error) if B is not in the name space. d) If no exception (execution error) occurs, it guarantees A is in the name space. e) None of the above (i.e., all of the above are correct). 11) Which of the following is true? a) In Python, a list value cannot be modified. b) In Python, the type of a variable cannot change during execution of a program. c) In Python, referencing a name not in the namespace results in an exception (execution error). d) All of the above. 12) What is printed by the following Python command if the value of val is 2: if 0 < (val/5) < val: print 0 else: print 1 a) 0 b) 1 c) A syntax error prevents it from being run. d) An exception occurs.

4 Figure 2 13) In Figure 2, what is printed by Line A if the user inputs a.2.z1.4 X.23 (without the quotes, with 2 blank spaces after the 4 and before the X)? a) az b) az c) azx d) a2z14x 14) In Figure 2, what is printed by Line B if the user inputs a.2.z1.4 X.23 (without the quotes, with 2 blank spaces after the 4 and before the X)? a) 12 b) 7 c) 4 d) 2 15) In Figure 2, what is printed by Line C if the user inputs a.2.z1.4 X.23 (without the quotes, with 2 blank spaces after the 4 and before the X)? a) 14 b) 9 c) 8 d) 5 None of the above. 16) In Figure 2, what is printed by Line C if the user does not input anything at the prompt, but simply presses the Enter (Return) key? a) a blank line b) 1 c) 0 d) Line C is not executed 17) Which statement about the command in Line D of Figure 2 is true? a) Depending on what the user inputs, it may be executed more than once. b) Depending on what the user inputs, it may never be executed. c) Depending on what the user inputs, it may be executed exactly once. d) All of the above are true.

5 Figure 3 18) In Figure 3, what is printed by Line A? a) day b) Good day c) e d) l 19) In Figure 3, what is printed by Line B? a) day b) Greetings c), d) H 20) Which of the following is not illustrated by Line C of Figure 3? a) a method invocation b) an argument c) a side effect d) a string e) None of the above (i.e., all are illustrated) 21) In Figure 3, what is printed by Line D? a) [Hello, Good day, Greetings, Hi] b) ['Hello', 'Good day', 'Greetings', 'Hi'] c) ['Hello', 'Good', 'day', 'Greetings', 'Hi'] d) 'Hello Good day Greetings Hi' 22) In Figure 3, what is printed by Line E? a) ['Good day', 'Greetings'] b) ['Good day'] c) ['Greetings', 'Hi'] d) ['Greetings']

6 Figure 4 23) In Figure 4, what is printed by Line A? a) mystrmystrmystr b) ('spam',3) c) spamspamspam d) an exception (execution error) occurs. 24) In Figure 4, if Line B is replaced with mylist.append(0), what is printed by Line C? a) [3, 'spam'] b) [3, 'spam', 0 ] c) [3, 'spam', [0 ]] d) [0, 3, 'spam'] 25) In Figure 4, if Line B is replaced instead with mylist[1]+= mystr, what is printed by Line C? a) [4, 'spam'] b) [3, 'spamspam'] c) [3, mystrmystr] d) an exception (execution error) occurs. 26) In Figure 4, if Line B is replaced instead with mystr[1]+= mystr, what is printed by Line D? a) ['spam', 'spam'] b) spspamam c) sspampam d) an exception (execution error) occurs.

7 27. Program question 20pts. Please, write on scrap paper first, then copy your answer to the next page. Make sure you put your name on the solution and hand it in at the end of the test. Requirements Your program should prompt the user to type some sentence(s) followed by enter. It should then print the original sentence(s) and the following statistics relating to the sentence(s): Number of words Number of characters (including white-space and punctuation) Percentage of characters that are alphanumeric Hints Assume any consecutive sequence of non-blank characters is a word. Your program does not need to do any error checking. If the user gives it erroneous input, it can crash. Your program does not need to be efficient or elegant. But it must work as described for full credit. Readability does matter. Make it readable! Do it on scrap first! Be clear about your indentation! Write legibly!! Remember the split method for strings. It will create a list of string subpieces using the split argument as the separator (if none provided, whitespace is the separator). For example: o aa bb cc.split() -> [ aa, bb, cc ] o bill.txt.split(. ) -> [ bill, txt ] o a:b:c.split( : ) -> [ a, b, c ] Example

8 CSE 231, Spring 10, Dr. Dillon, Exam 1 written solution Name: Section: # prompt for a sentence; echo the sentence and some statistics sentence = raw_input("type some sentence(s), followed by `Enter':\n") wordlist = sentence.split() # count the number of alphanumeric characters alphanumct = 0 for ch in sentence: if ch.isalnum(): alphanumct += 1 # calculate the percentage if len(sentence) > 0: percent = (float(alphanumct)/len(sentence))*100 percentstr = str(int(percent)) else: percentstr = "Cannot calculate percentage of empty string." # output the statistics print print "The sentence(s) you typed:" print sentence print print "Number of characters typed: ", len(sentence) print "Number of words typed: ", len(wordlist) print "Percent of alphanumeric characters: ", percentstr print

9 SCRATCH PAPER