Day 2: Review, ICS3U0, June 2017

Transcription

1 Day 2: Review, ICS3U0, June 2017 Bubble in your answers as directed. Use a pencil. Put your name on the scantron. Multiple Choice. Select the best answer. Applets 1. After you click a button, e.getactioncommand() holds: (a) the JButton s Action Listener (b) the text on the JButton (c) the JButton s Action Command (d) a and c (e) None of the above 2. This would change the colour to red: (a) g.setcolor(new Color(255,255,0)); (b) g.setcolor(new Color(0,0,0)); (c) g.setcolor(new Color(255,0,0)); (d) g.setcolor(new Color(0,255,0)); (e) g.setcolor(new Color(0,0,255)); 3. You would declare a JLabel globally if: (a) You needed to change it s text in actionperformed (b) You needed to change it s background to red (c) It had a lot of formatting. (d) It was a picture. (e) None of the above. 4. Red and green (in java) makes: (a) cyan (b) yellow (c) green (d) magenta (e) purple 5. Red and blue (in java) makes: (a) cyan (b) yellow (c) green (d) magenta (e) purple 6. Which colours make cyan? (a) red + blue (b) red + green (c) green + blue (d) red + green + blue 7. Which one is a string used to distinguish between buttons? (a) ActionListeners (b) ActionCommand (c) ActionPerformed (d) ActionEvent 8. Which one watches over a button and triggers an event? (a) ActionListeners (b) ActionCommand (c) ActionPerformed (d) ActionEvent 9. Which one is a method where events are processed? (a) ActionListeners (b) ActionCommand (c) ActionPerformed (d) ActionEvent 10. A can be used to create or display a string. (a) JLabel (b) JTextField (c) JRadioButton (d) JCheckbox (e) JButton 11. Methods that cannot be called on a JLabel include: (a) settext (b) setfont (c) setforeground (d) setbackground (e) setvisible 12. Which widgets have events? (a) JLabel (b) JTextField (c) JButton (d) JTextArea (e) Panel 13. What category of method is.settext? (a) accessor (b) mutator (c) constructor (d) facilitator

2 14. What category of method is this line: JLabel title = new JLabel ("Click"); (a) accessor (b) mutator (c) constructor (d) facilitator 15. What category of method is e.getactioncommand()? (a) accessor (b) mutator (c) constructor (d) facilitator 16. Which code has the correct order to make these widgets appear on the screen? JLabel n1 = new JLabel ("Tiger"); JButton n2 = new JButton ("Elephant"); JTextField n3 = new JTextField (6); (a) add (n3); add (n2); add (n1); (b) add(n1); add(n2); add(n3); (c) add (n3); add (n1); add (n2); (d) add (n2); add (n1); add (n3); The next three questions refer to this screen: 17. How many widgets are on this screen? (a) 4 (b) 5 (c) 6 (d) 10 (e) How many actionlisteners would be declared in init? (a) 0 (b) 1 (c) 2 (d) 3 (e) How many JLabels are on this screen? (a) 0 (b) 1 (c) 2 (d) 3 (e) Why are actionlisteners useful? (a) They signal actionperformed when a button is clicked. (b) They make a program responsive. (c) They pass the ActionListener to the ActionEvent so it knows which button is pressed. (d) All of the above. (e) None of the above. 21. Which type of widget is not needed by this tent screen? (a) JTextField (b) JButton (c) JLabel (d) JPicture (e) All of the above are needed 22. Which method is not needed to make this tent screen? (a) Init (b) ActionPerformed (c) Main (d) CreateImageIcon 23. Which type of widget on the tent screen needs to be global? (a) JTextField (b) JButton (c) JPicture (d) Int (e) Main

3 24. When you add the line implements actionlistener in your applet, you are: (a) Committing to use the init method in your code. (b) Committing to use the main method in your code. (c) Committing to use the swing libraries widgets (d) Committing to use the actionperformed method in your code. 25. What line of code has an error: (a) JButton next = new JButton ( Next screen ); (b) next.setactioncommand ("2"); (c) next.addactionlistener ( ); (d) next.setforeground(color.white); (e) next.setbackground(color.black); 26. Which isn t a method in an applet? (a) createimageicon (b) main (c) actionperformed (d) init 27. Which phase of the PDLC has beta testing? (a) Analysis (b) Design (c) Code (d) Evaluate 28. Which phase of the PDLC would involve brainstorming a brand new game idea? (a) Analysis (b) Design (c) Code (d) Evaluate 29. Which phase of the PDLC involved drawing detailed level maps and drawing artwork? (a) Analysis (b) Design (c) Code (d) Evaluate 30. Which phase of the PDLC involves drawing flow charts? (a) Analysis (b) Design (c) Code (d) Evaluate 31. Which phase of the PDLC involves writing a script/storyline? (a) Analysis (b) Design (c) Code (d) Evaluate 32. This structure chart was used to design a maze game. Which of the following statements is false? (a) There are 3 screens in the game. (b) The game will be an applet. (c) ActionPerformed calls three other methods. (d) isvalid returns a Boolean value. (e) The program has more void methods than any other return type.

4 33. This screen flow diagram is used to design a checkers game. Which statement is true? (a) There are 6 screens. (b) The first screen that will appear is instructions 1. (c) All arrows on a screen flow diagram must begin at a button. (d) Only the buttons that are important to the screen flow are displayed. (e) On a screen flow diagram, a screen can only connect to a maximum of three other screens. 34. What is false about this screen flow diagram? (to the right) (a) The first screen to appear is Welcome. (b) The first screen to appear is numbered 0. (c) The level 1 screen can go to 3 screens. (d) The level 2 screen can go to 5 screens. (e) There are 6 screens. 35. Which is false about screen flow diagrams? (a) All screens must be connected with arrows. (b) A screen should never have more than 6 buttons leading to other screens. (c) A screen needs a unique name. (d) The first screen a user will see is numbered with 0. (e) C and B. 36. Why are screen flow diagrams useful? (a) They provide details about the layout and colour scheme of the screens. (b) They help programmers write comments for their code so debugging is easier. (c) They are used in the Design phase of the PDLC to layout navigations in the program. (d) They help design the details of the code, including input, output and processing. (e) They help the programmer understand the structure of Strings and which char is in which location. 37. Which is true? (a) You should new an object in actionperformed. (b) showstatus( HI ); would print HI in the status bar. (c) Panels, including screen panels, never need to be declared globally. (d) The colour 255, 0, 255 is cyan. (e) To add a picture, you need to add the createimageicon method to your applet. 38. Which is false? (a) The speed of finding the maximum in the array is O(n). (b) The speed of printing the array is O(n). (c) The speed of Bin Sort is O(n). (d) The speed of Bubble Sort is O(n 2 ), in the average case. (e) The speed of selection sort is O(n log n), in the average case.

5 For the next three questions, consider this flowchart: 39. Which widget is required for the get height parallelogram? (a) JLabel (b) JTextField (c) JButton (d) JTextArea (e) Panel 40. Which widget is required for the you can ride pencil-shape? (a) JLabel (b) JTextField (c) JButton (d) JTextArea (e) Panel 41. Which code construct is required for the height < 54 diamond? (a) loop (b) String (c) main method (d) System.out (e) Boolean expression in an if 42. Why are flow charts useful? (a) They provide details about the layout and colour scheme of the screens. (b) They help programmers write comments for their code so debugging is easier. (c) They are used in the Design phase of the PDLC to layout navigations in the program. (d) They help design the details of the code, including input, output and processing. (e) They help the programmer understand which element is in which index. 43. When a programmer disables buttons when they should not be clicked, they are using this priciple of good user interface design. 44. When a programmer uses JButtons instead of JTextfields when possible, they are using this priciple of good user interface design. 45. When a programmer provides clear titles on the top of their screens, they are using this priciple of good user interface design. 46. When a programmer uses colour and pictures, they are using this priciple of good user interface design. 47. When a programmer has a reset or undo button, they are using this priciple of good user interface design. 48. When a programmer groups like items with like items, they are using this priciple of good user interface design. 49. When a programmer puts prompts in front of JTextFields, they are using this priciple of good user interface design.

6 50. When a programmer places widgets in the order needed, they are using this priciple of good user interface design. More Loops The next four questions refer to this flowchart. 51. Which part of the flow chart tests the loop stopping condition: (a) Start (b) num=0 (c) num < 10 (d) num (e) num Which part of the flow chart initializes the loop stopping variable: (a) Start (b) num=0 (c) num < 10 (d) num (e) num Which part of the flow chart moves toward loop stopping condition: (a) Start (b) num=0 (c) num < 10 (d) num (e) num Which part of the flow chart is the steps to repeat: (a) Start (b) num=0 (c) num < 10 (d) num (e) num If you wish to print the numbers from 1 to 60, what number should fill in the blank? for (int i = 1; i < ; i++) { System.out.println(" "+i); (a) 59 (b) 60 (c) 61 (d) 62 (e) None of the previous 56. If you wish to print the numbers from 1 to 100, what number should fill in the blank? for (int i = 1; i < ; i++) { System.out.println(" "+i); (a) 101 (b) 99 (c) 98 (d) 102 (e) None of the previous Arrays 57. When declared, arrays must have: (a) a type (b) a name (c) a size (d) a dimension (e) all of the previous 58. How do you write the third element from the beginning in an array called a in java? (a) a[2] (b) a(2) (c) a[3] (d) a(3) (e) none of the previous 59. Which of the following is correct? (a) int a[] = new int[2]; (b) int a[] = new int(2); (c) int a = new int[2]; (d) int a = new int[3]; (e) int a = new int(2);

7 60. Which is the correct array declaration? (a) int towns[]={"atown", "Bream", "Broda", "Calgari", "Frenzia", "Newtown", "Roetown"; (b) String towns[]=("atown", "Bream", "Broda", "Calgari", "Frenzia", "Newtown", "Roetown"); (c) String towns ={"Atown", "Bream", "Broda", "Calgari", "Frenzia", "Newtown", "Roetown"; (d) String towns[] ={"Atown", "Bream", "Broda", "Calgari", "Frenzia", "Newtown", "Roetown"; (e) char towns =("Atown", "Bream", "Broda", "Calgari", "Frenzia", "Newtown", "Roetown"); 61. Assume int t[] = {0,1,2,3; What is t.length? (a) 0 (b) 2 (c) 3 (d) 4 (e) How can you initialize an array of two characters to 'a' and 'b'? (a) char chararray []= new char[2]; chararray = {'a', 'b'; (b) char chararray [2] = {'a', 'b'; (c) char chararray []= {'a', 'b'; (d) char chararray []= new char[]{'a', 'b'; (e) char chararray []={ a, b ); 63. An array can: (a) grow to a larger size when the program is running. (b) have different types put in it. (c) be re-declared. (d) be re-initialised. (e) have a name that is two words with a space in the middle. 64. The code is designed to find the position of the word octopus in the array shown. What is wrong with it? String a[]={ cat, dog, giraffe, goat, monkey, octopus, turkey, snake ; int pos=-1; for(int i=0; i<a.length; i++) { if (a[i]== octopus ) pos = i; System.out.println( Octopus is in position +pos); (a) the for loop runs to size instead of a.length (b) the if should use.equals instead of == (c) pos should be initialized to 0 because that is the first spot in the array (d) the for loop should have a semi-colon after it. (e) the if needs curly braces. 65. Referring to the flow chart below, which array function is displayed? (a) Minimum (b) Maximum (c) Search (d) Bubble sort (e) Bin sort

8 66. Referring to the flow chart below, which array function is displayed? (a) Bin sort (b) Linear Search (c) Maximum (d) Sum (e) Print 67. Referring to the flow chart below, which array function is displayed? (a) Minimum (b) Maximum (c) Sum (d) Sum under 9 (e) Sum over Why are memory diagrams useful for arrays? (a) They provide details about the layout and colour scheme of the screens. (b) They help programmers write comments for their code so debugging is easier. (c) They are used in the Design phase of the PDLC to layout navigations in the program. (d) They help design the details of the code, including input, output and processing. (e) They help the programmer understand which element is in which index. 69. Which of the following statements is valid? (a) int i = new int(30); (b) double d[] = new int [30]; (c) int i []= {3, 4, 3, 2; (d) char c []= new char(); (e) char c [] = new char[4]{'a', 'b', 'c', 'd'; 70. If you wanted to sort a list of numbers that was sorted, but had one new thing added to the end, you would use: (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort 71. If you wanted to sort a list of names that was sorted, but had one new thing added to the end, you would use: (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort 72. If you wanted to sort a list of 5,000,000 names in random order, you would use: (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort 73. If you wanted to sort a list of 5,000,000 numbers in random order, you would use: (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort 74. You have 3,000,456 integers all between 0 and 3. How would you sort them? (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort 75. The fastest sorting algorithm we learned was: (a) Bubble Sort (b) Bin Sort (c) Insertion Sort (d) Shaker Sort (e) Selection Sort

9 76. Referring to the code below, what value for X will print all elements of array "values"? int values [] = {0, 1, 2, 3, 4, 5, 6, 7; for (int i = 0 ; i < X ; i++) System.out.println (values [i]); (a) 1 (b) 7 (c) 8 (d) 9 (e) none, there is an error in the code. 77. Consider the following code int number[] = new int[5]; After execution of this statement, which of the following are true? (a) number[0] is undefined (b) number[5] is undefined (c) number[4] is null (d) number[2] is 0 (e) number.size () is In the notation for the time that an algorithm takes, n refers to: (a) the number of operations (b) the speed (c) the number of seconds (d) the size of the array (e) none of the above 79. Which error appears in the following flowchart? (a) n=0 should be in a parallelogram. (b) The variable i is not initialized. (c) There should not be two arrows going to j++. (d) The reference to the i, jth element is confusing. (e) All of the above. 80. Why would you choose to use a for loop over a while loop? (a) it is more compact (b) you are using a counting loop (c) you are working with arrays (d) all of the above (e) a and c 81. What array function is shown by this code? int a[]={23, 34, 56, 1, 2, 3, 34, 99, 0, 45, 2; int m=0; for(int i=0; i<a.length; i++) m+=a[i]; System.out.println( The mystery result is +m); (a) maximum (b) linear search (c) binary search (d) sum (e) average

10 82. An ArrayIndexOutOfBoundsException is an error that: (a) occurs when you put elements of different types in an array (b) occurs if you go off the end of an array (c) occurs if you make a partially filled array when a full array is required. (d) occurs after a NullPointer exception. (e) must happen in linear search 83. The pictures for the game of sokoban are named using numbers. Why? (a) Because numbers are used in math and that makes them easier to use. (b)because Strings would make meaningful names like brick or box, less meaningful is better. (c) Because String use.equals and double quotations. Those are annoying to type. (d) Because it is June. Integers work well in June. (e) Because arrays can only be declared as integers. 84. What is declared and set up in the following section of code? JButton b[]; public void init() { b=new JButton[26]; for(int i=0; i<b.length; i++) { b[i]=new JButton(? ); b[i].setactioncommand(i+ ); b[i].addactionlistener(this); add(b[i]); (a) an array of 25 local JButtons (their text can t change). (b) an array of 25 global JButtons (c) an array of 26 local JButtons. (d) an array of 26 global JButtons (e) an applet 85. The code is designed to find the minimum number in the array shown. What is wrong with it? int a[]={1, 34, 516, 78, 89, 100, 234, 54, 3, 27; int min = 0; for (int i=0; i<a.length; i++) { if (min>a[i]) min=a[i]; System.out.println( The minimum value is + min); (a) the min should be initialized to a[0] not 0. (b) the array shouldn t be called a. array would be more appropriate (c) the for loop should have a semi-colon after it. (d) the if needs curly braces. (e) the if line should read: if(min<a[i]) 86. Which puts the Big-Oh notation speeds in the correct order, from fastest to slowest? (a) O(1), O(log n), O(n), O(n log n), O(n 2 ), O(n 3 ), O(2 n ) (b) O(n log n), O(log n), O(n), O(2 n ), O(n 2 ), O(n 3 ), O(1) (c) O(1), O(log n), O(n log n), O(n), O(n 2 ), O(n 3 ), O(2 n ) (d) O(1), O(log n), O(n log n), O(2 n ), O(n), O(n 2 ), O(n 3 ) (e) O(2 n ), O(log n), O(n log n), O(1), O(n), O(n 2 ), O(n 3 )

11 87. Which trace is of selection sort? (a) (b) Which trace is of bubble sort? (a) (b) (c) (c) (d) (d) How many changes are needed to convert this bubble sort code from and integer to a char array? public void bubble (int a []) { int n = a.length; for (int i = 0 ; i < n - 1 ; i++) { for (int j = 0 ; j < n i ; j++) { if (a [j + 1] < a [j]) { int temp = a [j]; a [j] = a [j + 1]; a [j + 1] = temp; (a) 0 (b) 1 (c) 2 (d) 6 (e) none of the previous. 90. What does this code do? int findme = IO.inputInt("Find what? "); int pos = -1; for (int i = 0 ; i < array.length ; i++) { if (array [i] == findme) pos = i; if(pos==-1) System.out.println("Didn t find it"); else System.out.println("It is in position "+pos); (a) find the max (b) initialize (c) binary search (d) search (e) selection sort

12 91. What operation does this code do? int m = a[0]; for (int i = 0; i < a.length; i++) { if (m < a[i]) m = a[i]; System.out.println(m); (a) min (b) max (c) sum (d) average (e) print 92. Denise Melanson s inquest ruled that: (a) It was her nurse s fault that she died. (b) Chemotherapy pumps should only be used in a hospital setting. (c) The system was a fault. (d) User Interfaces should be visually appealing. (e) All of the above. 93. The PDLC is important because: (a) Dividing work is easier when you know what work is required. (b) Good planning means that a large team of people can work together seamlessly. (c) Programs need to be thoroughly tested to remove bugs. (d) It is important that the entire process begins with a good idea or high concept statement. (e) All of the above. 94. Why are algorithms important to computer science? (a) Efficiently written algorithms can significantly improve the running time of a program. (b) Jon Bentley was a programmer. (c) Loops allow code to repeat quickly. (d) Algorithms are a series of steps that complete a task. (e) Animation and rendering are killer aps. 95. Why does the array index start at 0? (a) Because the 0 th element starts at the beginning of the array memory allocation. It is easier to access in memory. (b) There is no reason to waste a perfectly good number (0). (c) It s related to binary, which is used on computer hardware. (d) It is easier to make loops < array.length. (e) All of the above. 96. Why do loops use i as the counting variable. (a) Because i takes less space on the screen than x. (b) Because a would be confusing. (c) Because y is in an inconvenient place on the keyboard. (d) Because i stands for array index. (e) Because i isn t a common vowel and is rarely typed. 97. Why are arrays useful? (a) They don t take up much memory. (b) They work well with control structures like ifs. (c) All of their operations can be done in constant time (Big Oh notation). (d) You can quickly loop through them, changing all of the elements easily. (e) They help develop animation.

13 98. Why is it important to design user interfaces well? (i) If devices are intuitive, they are easier to use. (ii) Error checking makes devices safer. (iii) Visually appealing user interfaces will attract more customers. (a) i and iii (b) ii and iii (c) iii (d) i and ii (e) none of the previous 99. When do you use a while loop over a for loop? (a) When you are counting a set number of times. (b) With an array. (c) When you have a complex loop stopping condition involving and or &&. (d) A & B (e) All of the above Why should you learn to program? (a) Because the singularity is coming and you want to be able to communicate with our new masters. (b) Because it is a dying art like knitting and cooking and it needs preserving. (c) Because computers are being used everywhere and it will be useful in your future jobs. (d) Because there are videos that tell you that you should on the internet. (e) Because Ms. Gorski says so.