Question Hot Seat

1. Question Hot Seat public MyConstructor (int a, int b) { index = a+b; } • Parameters • Class Name • Body • Modifier DBAC Please put match these choices to these boxes from left to right

2. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 Which of the following is invalid identifier? • a. GoodVar • b. $Good123Var • c. Good_123Var • d. %Good$Var

3. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 How would you define a Java array? • a. GoodVar • b. $Good123Var • a. Good_123Var • a. %Good$Var

4. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 How would you define a Java array? • a. a collection of data values of different types • b. a collection of data values of the same type • c. a collection of characters that incidentally form a string • d. a collection of primitive data types

5. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 How would you define a Java array? • a. a collection of data values of different types • b. a collection of data values of the same type • c. a collection of characters that incidentally form a string • d. a collection of primitive data types

6. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 What are the two ways that a Java array can be declared? • a.<type>[ ] <arrayname>; <type> <arrayname>; • b. <type> <arrayname>[ ]; <type> <arrayname>;[ ] • c. [ ]<type> <arrayname>;<type>[ ] <arrayname>; • d. <type>[ ] <arrayname>;<type> <arrayname>[ ];

7. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 What are the two ways that a Java array can be declared? • a.<type>[ ] <arrayname>; <type> <arrayname>; • b. <type> <arrayname>[ ]; <type> <arrayname>;[ ] • c. [ ]<type> <arrayname>;<type>[ ] <arrayname>; • d. <type>[ ] <arrayname>;<type> <arrayname>[ ];

8. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 Which of the following declares an array of integers of size 20? • a.int[ ] a = int[20]; • b. int[ ] a = new int[20]; • c. int a = new int[19]; • d. int a[ ] = new int[19];

9. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 Which of the following declares an array of integers of size 20? • a.int[ ] a = int[20]; • b. int[ ] a = new int[20]; • c. int a = new int[19]; • d. int a[ ] = new int[19];

10. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 How would we access the 12th element of the array, x? • a.x(12); • b. x(11); • c. x[12]; • d. x[11];

11. 1000 Ask Audience 50-50 Call a friend 500 300 200 100 How would we access the 12th element of the array, x? • a.x(12); • b. x(11); • c. x[12]; • d. x[11];

12. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Why are loops particularly useful for array operations? • a. Because loops easily traverse through the indexes of the array. • b. Because loops solve problems that otherwise would not be solvable without them. • c. Because loops take less time to run than conventional coding without loops. • d. Loops do not aid in the processing of arrays.

13. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Why are loops particularly useful for array operations? • a. Because loops easily traverse through the indexes of the array. • b. Because loops solve problems that otherwise would not be solvable without them. • c. Because loops take less time to run than conventional coding without loops. • d. Loops do not aid in the processing of arrays.

14. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 What does the following program do?double x = 0, unknown;for (int j = 0; j < someArray.length; j++){ x+=someArray[j];}unknown = x /someArray.length; • a. Computes the sum of the doubles in the array, someArray. • b. Deletes all the doubles in the array, someArray. • c. Computes the average of all the doubles in the array, someArray • d. Computes the dot product of all the doubles in the array, someArray.

15. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 What does the following program do?double x = 0, unknown;for (int j = 0; j < someArray.length; j++){ x+=someArray[j];}unknown = x /someArray.length; • a. Computes the sum of the doubles in the array, someArray. • b. Deletes all the doubles in the array, someArray. • c. Computes the average of all the doubles in the array, someArray • d. Computes the dot product of all the doubles in the array, someArray.

16. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Given a value X, return the index of X in the array, if such X exists. Otherwise, return NOT_FOUND. We assume there are no duplicate entries in the array.What are the two possible outcomes in this problem? • a. linear search and binary search • b. -1 and X • d. successful and unsuccessful • c. an index and a value

17. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Given a value X, return the index of X in the array, if such X exists. Otherwise, return NOT_FOUND. We assume there are no duplicate entries in the array.What are the two possible outcomes in this problem? • a. linear search and binary search • b. -1 and X • d. successful and unsuccessful • c. an index and a value

18. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 When would a programmer be forced to pick a linear search over a binary search? • a. When the items in the array are in ascending order • b. When the items in the array are in descending order • d. Linear search is never a better choice than binary search. • c. When the items in the array are unsorted

19. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 When would a programmer be forced to pick a linear search over a binary search? • a. When the items in the array are in ascending order • b. When the items in the array are in descending order • d. Linear search is never a better choice than binary search. • c. When the items in the array are unsorted

20. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Which of the following best describes the protocol for a selection sort? • Identify the largest element.Place the element at the beginning of a target listRepeat • b. Identify the median of the listSplit the list into two halves, those smaller and those larger than the medianPerform the same sort on each of the smaller halves • c. Identify the smallest element of the listPlace the element in the beginning of the target list Repeat • d. Identify the median element of the listPlace the element in the beginning of a target list Repeat

21. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 Which of the following best describes the protocol for a selection sort? • Identify the largest element.Place the element at the beginning of a target listRepeat • b. Identify the median of the listSplit the list into two halves, those smaller and those larger than the medianPerform the same sort on each of the smaller halves • c. Identify the smallest element of the listPlace the element in the beginning of the target list Repeat • d. Identify the median element of the listPlace the element in the beginning of a target list Repeat

22. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 What is the biggest number of computations made for a binary search on a sorted array of size 64? • a) 3 • b) 5 • c) 6 • d) 8

23. 32000 Ask Audience 50-50 Call a friend 16000 8000 4000 2000 What is the biggest number of computations made for a binary search on a sorted array of size 64? • a) 3 • b) 5 • c) 6 • d) 8

24. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 What is wrong with the following code?int product = 0, count=0;while (product < 2500){ product *= 5; count++;} • a. the syntax of the while statement is invalid • b. the operator, *=, does not exist. • c. it has an infinite loop • d. the count variable is initialized incorrectly.

25. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 What is wrong with the following code?int product = 0, count=0;while (product < 2500){ product *= 5; count++;} • a. the syntax of the while statement is invalid • b. the operator, *=, does not exist. • c. it has an infinite loop • d. the count variable is initialized incorrectly.

26. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 Assume you had a class BankInfo that contained three data members: accountNumber, pinNumber, and name. The data member name must be searchable by other classes.What access modifiers would you apply to these members? • b. make accountNumber public, pinNumber private, and name public • a. make accountNumber private, pinNumber private, and name public • c. make them all private • d. make them all public

27. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 Assume you had a class BankInfo that contained three data members: accountNumber, pinNumber, and name. The data member name must be searchable by other classes.What access modifiers would you apply to these members? • b. make accountNumber public, pinNumber private, and name public • a. make accountNumber private, pinNumber private, and name public • c. make them all private • d. make them all public

28. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 What is the difference in path name specification between the UNIX and Windows operating systems? • b. UNIX allows for spaces in file and directory names while Windows does not. • a. There are no .exe files in UNIX but there are .exe files in Windows • c. UNIX separates directories from subdirectories with forward slashes while Windows separates directories with backslashes. • d. There is no difference

29. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 What is the difference in path name specification between the UNIX and Windows operating systems? • b. UNIX allows for spaces in file and directory names while Windows does not. • a. There are no .exe files in UNIX but there are .exe files in Windows • c. UNIX separates directories from subdirectories with forward slashes while Windows separates directories with backslashes. • d. There is no difference

30. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 Assume you want to read the contents of a file and display to the monitor. Which file I/O classes can we use to accomplish this? • b. FileInputStream or DataInputStream • a. FileInputStream or FileOutputStream • c. FileOutputStream or DataOutputStream • d. DataInputStream or DataOutputStream

31. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000 Assume you want to read the contents of a file and display to the monitor. Which file I/O classes can we use to accomplish this? • b. FileInputStream or DataInputStream • a. FileInputStream or FileOutputStream • c. FileOutputStream or DataOutputStream • d. DataInputStream or DataOutputStream

32. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000

33. 1000000 Ask Audience 50-50 Call a friend 500000 250000 125000 64000