CSCI 160 Midterm Review

1. CSCI 160 Midterm Review Rasanjalee DM

2. Multiple Choice Questions

3. Question • The Java compiler translates Java programs into machine language programs. TRUE FALSE

4. Answer • The Java compiler translates Java programs into machine language programs. • [FALSE]

5. Question • System.out is an example of a method. TRUE FALSE

6. Answer • System.out is an example of a method. TRUE FALSE [FALSE]

7. Question • ice-cream is an illegal identifier in Java. • TRUE FALSE

8. Answer • ice-cream is an illegal identifier in Java. • TRUE FALSE • [TRUE]

9. Question • Constructors have return type void. • TRUE FALSE

10. Answer • Constructors have return type void. • TRUE FALSE • [FALSE]

11. Fill in the Blanks

12. Questions • Every variable in Java must be __________ before it is used. • Single quotes are used with constants of the __________ type.

13. Answers • Every variable in Java must be __________ before it is used. [declared] • 2. Single quotes are used with constants of the __________ type. [char]

14. Questions • A(n) __________ is used for signaling the end of the input. • A(n) __________ is an action that an object can take and is specified in the class definition. • Compiling a file called Game.java will produce a file called __________.

15. Answers • A(n) __________ is used for signaling the end of the input. [sentinel value] • A(n) __________ is an action that an object can take and is specified in the class definition. [method] • Compiling a file called Game.java will produce a file called __________. [Game.class]

16. Question • A(n) __________ is a data item that belongs to an object. • __________ is the word used to say that there are no restrictions on the use of a method or data item can be used. • The reserved word __________ can be used as a name for the calling the current object.

17. Answer • A(n) __________ is a data item that belongs to an object. • [instance variable] • 4. __________ is the word used to say that there are no restrictions on the use of a method or data item can be used. • [public] • 5. The reserved word __________ can be used as a name for the calling object. • [this]

18. Short Answer Questions

19. Question • Add parentheses to the following expressions to indicate how Java will interpret them. (a) a * b * c - d / e(b) a + - b * c - d

20. Answer • ((a * b) * c) - (d / e) • (a + ((-b) * c)) - d

21. Question • After the following statements have been executed, how many Fraction objects will exist, not counting garbage objects? Fraction f1 = new Fraction(1, 2); Fraction f2 = new Fraction(3, 5); Fraction f3 = f2;f2 = null;f1 = f2;

22. Answer • One

23. Question • Answer the questions below about this class. • What are the names of the instance variables declared in this class? • What are the signatures of the constructors declared in this class? • What are the names of the parameters declared in this class? • What are the signatures of the methods declared in this class? e) What are the names of the constants declared in this class?

24. Answer • Answer the questions below about this class. • What are the names of the instance variables declared in this class? name, slalomPoints, giantSlalomPoints, superGPoints, ussaNumber b) What are the signatures of the constructors declared in this class? public Skier (String name, String ussaNumber) c) What are the names of the parameters declared in this class? name, ussaNumber • What are the signatures of the methods declared in this class? public String getBestEvent() e) What are the names of the constants declared in this class? MAXIMUM_POINTS

25. Code Analysis

26. Question • What does the following program print? int[] arr = {1, 1, 0, 0, 0}; for (int i = 2; i < arr.length; i++) arr[i] = arr[i-1] + arr[i-2];

27. Answer • What does the following program print? 11235 index = 0 1 2 3 4 int[] arr = {1, 1, 0, 0, 0}; for (int i = 2; i < arr.length; i++) arr[i] = arr[i-1] + arr[i-2]; iarr[i-1] arr[i-2] arr[i] arr 2 1 1 1+1 =2 11200 3 2 1 2+1 =3 11230 4 3 2 2+3 = 5 11235

28. Question • Show the EXACT output the following programs generate: public class e21 { public static void main (String args[]) { intnum = 4; printNumbers(num); } private static void printNumbers(int n) { for (int i=1; i <= n; i++) { for (int k=1; k <= 2*(i-1)+1; k++) System.out.print(i); System.out.println(); } } }

29. Answer 1 222 33333 4444444

30. Write Java Code

31. Question • Write one line java statement declaring and creating a 1-d double array that stores whether or not precipitation was recorded on each day of one (non-leap year)

32. Answer • boolean[] precipRecord = new boolean[365];

33. Question • Write a one-line java statement declaring and creating a 2-d array named matrix with 24 rows and 80 columns.

34. Answer • double[][] matrix = new double[24][80];

35. Question • Write 1 or more java statements to display all the elements of the last column of the 2-d array matrix from the previous part

36. Answer for(inti=0; i<matrix.length; i++) System.out.println(matrix[i][79]);

37. Question • Write 1 or more java statements to compute and print the product of all the elements in the second row of the 2-d array matrix

38. Answer double product = 1 for(inti=0; i<matrix.length; i++) { product *= matrix[1][i]; } System.out.println(product);

39. Question • Write 1 or more java statements to compute and print the number of upper case characters in a saying (stored in variable saying)

40. Answer int upper= 0; for(inti=0;i<saying.length;i++) { if(saying.charAt(i)>=‘A’ && saying.charAt(i)<=‘Z’) { upper+; } } System.out.println(upper);

41. Question • Write a method named toBinary that accepts an integer as a parameter and returns a string of that number's representation in binary. For example, the call of toBinary(42) should return "101010". We will assume a positive parameter.

42. Answer private static String toBinary(int num) { if (num == 0) return "0"; String str=""; while (num != 0) { str = (num%2)+str; num /= 2; } return str; }