Name:_______________________ Sample Exam
Covers Chs 21-25
Part I: Questions: (1 pts each)
1. ________ is a data structure to store data in sequential
order.
a. A list
b. A set
c. A tree
d. A stack
e. A queue
2. A __________ (with no duplicate elements) has the
property that for every node in the tree the value of
any node in its left subtree is less than the value of
the node and the value of any node in its right
subtree is greater than the value of the node.
a. binary tree
b. binary search tree
c. list
d. linked list
3. The ________ is to visit the left subtree of the current
node first, then the current node itself, and finally
the right subtree of the current node.
a. inorder traversal
b. preorder traversal
c. postorder traversal
d. breadth-first traversal
4. The _________ is to visit the nodes level by level.
First visit the root, then all children of the root
from left to right, then grandchildren of the root
from left to right, and so on.
a. inorder traversal
b. preorder traversal
c. postorder traversal
d. breadth-first traversal
5. To remove the root, you need to start a process by first
placing _______ to the place of the root and move it
down to maintain the heap property.
a. one of the root's children
b. the larger child of the root
c. the smaller child of the root
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d. the last node in the heap
6. To add a new node, you need to start a process by first
placing it as _______ and move it up to main the heap
property.
a. the new root
b. the last node in the heap
c. the left child of the root
d. the right child of the root
7. Which data structure is appropriate to store patients in
an emergency room?
a. Stack
b. Queue
c. Priority Queue
d. Linked List
8. Which data structure is appropriate to store customers
in a clinic for taking flu shots?
a. Stack
b. Queue
c. Priority Queue
d. Array List
e. Linked List
9.
a.
b.
c.
d.
Fill in the code in Comparable______ c = new Date();
<String>
<?>
<Date>
<E>
10. Suppose List<String> list = new ArrayList<String>.
Which of the following operations are correct?
a. list.add("Red");
b. list.add(new Integer(100));
c. list.add(new java.util.Date());
d. list.add(new ArrayList());
11. To declare a class named A with two generic types, use
a. public class A<E> { ... }
b. public class A<E, F> { ... }
c. public class A(E) { ... }
d. public class A(E, F) { ... }
12. The method header is left blank in the following code.
Fill in the header.
public class GenericMethodDemo {
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public static void main(String[] args ) {
Integer[] integers = {1, 2, 3, 4, 5};
String[] strings = {"London", "Paris", "New York",
"Austin"};
print(integers);
print(strings);
}
__________________________________________ {
for (int i = 0; i < list.length; i++)
System.out.print(list[i] + " ");
System.out.println();
}
}
a.
b.
c.
d.
public
public
public
public
static
static
static
static
13. To create
a. <E extends
b. <E extends
c. <E>
d. <E extends
void
void
void
void
print(Integer[] list)
print(String[] list)
print(int[] list)
print(Object[] list)
a generic type bounded by Number, use
Number>
Object>
Integer>
14. Which of the following declarations use raw type?
a. ArrayList<Object> list = new ArrayList<Object>();
b. ArrayList<String> list = new ArrayList<String>();
c. ArrayList<Integer> list = new ArrayList<Integer>();
d. ArrayList list = new ArrayList();
Key:d
15. Is ArrayList<Integer> a subclass of ArrayList<Object>?
a. true
b. false
16. Is ArrayList<Integer> a subclass of ArrayList<?>?
a. true
b. false
17. Does <? super Number> represent a superclass of Number?
a. yes
b. no
18. Which of the data type below does not allow duplicates?
a.
Set
3
b.
c.
d.
e.
List
Vector
Stack
LinkedList
19. Which of the following data types does not implement
the Collection interface?
a.
HashSet
b.
TreeSet
c.
ArrayList
d.
LinkedList
e.
Map
20. Which of the data type below could be used to store
elements in their natural order based on the compareTo
method.
a.
HashSet
b.
TreeSet
c.
LinkedHashSet
d.
Collection
e.
Set
21. If you want to store non-duplicated objects in the
order in which they are inserted, you should use
____________.
a.
HashSet
b.
LinkedHashSet
c.
TreeSet
d.
ArrayList
e.
LinkedList
22. Which of the following is correct to perform the set
union of two sets s1 and s2.
a.
s1.union(s2)
b.
s1 + s2
c.
s1.addAll(s2)
d.
s1.add(s2)
23. Analyze the following code.
import java.util.*;
public class Test {
public static void main(String[] args) throws Exception {
Set set = new TreeSet();
set.add("Red");
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set.add("Green");
set.add("Blue");
System.out.println(set.first());
}
}
a.
The program displays Red
b.
The program displays Blue
c.
The program displays Green
d.
The program may display Red, Blue, or Green.
e. The program cannot compile, because the first() method
is not defined in Set.
24. Analyze the following code.
import java.util.*;
public class Test {
public static void main(String[] args) throws Exception {
TreeSet set = new TreeSet();
set.add("Red");
set.add("Green");
set.add("Blue");
System.out.println(set.last());
}
}
a.
The program displays Red
b.
The program displays Blue
c.
The program displays Green
d.
The program may display Red, Blue, or Green.
e. The program cannot compile, because the first() method
is not defined in Set.
25. Analyze the following code.
import java.util.*;
public class Test {
public static void main(String[] args) throws Exception {
TreeSet set = new TreeSet();
set.add("Red");
set.add("Yellow");
set.add("Green");
set.add("Blue");
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SortedSet temp = set.headSet("Purple");
System.out.println(temp.first());
}
}
a.
The program displays Blue
b.
The program displays Red
c.
The program displays Green
d.
The program displays Yellow
e. The program displays Purple
26. Analyze the following code.
import java.util.*;
public class Test {
public static void main(String[] args) throws Exception {
TreeSet set = new TreeSet();
set.add("Red");
set.add("Yellow");
set.add("Green");
set.add("Blue");
SortedSet temp = set.tailSet("Purple");
System.out.println(temp.first());
}
}
a.
The program displays Red
b.
The program displays Blue
c.
The program displays Green
d.
The program displays Yellow
e. The program displays Purple
27. Which method do you use to test if an element is in a
set or list named x?
a.
(element instanceof List) || (element instanceof Set)
b.
x.in(element)
c.
x.contain(element)
d.
x.contains(element)
e.
x.include(element)
28. Which method do you use to find the number of elements
in a set or list named x?
a.
x.length()
b.
x.count()
c.
x.counts()
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d.
e.
x.size()
x.sizes()
29. Which method do you use to remove an element from a set
or list named x?
a.
x.delete(element)
b.
x.remove(element)
c.
x.deletes(element)
d.
x.removes(element)
e.
None of the above
30. What is the printout of the following code?
List<String> list = new ArrayList<String>();
list.add("A");
list.add("B");
list.add("C");
list.add("D");
for (int i = 0; i < list.size(); i++)
System.out.print(list.remove(i));
a.
ABCD
b.
AB
c.
AC
d.
AD
e.
ABC
31. Which of the following is correct to sort the elements
in a list lst?
a. lst.sort()
b. Collections.sort(lst)
c. Arrays.sort(lst)
d. new LinkedList(new String[]{"red", "green", "blue"})
32. Which of the following statements are true?
a. Collections.shuffle(list) returns a new list while the
original list is not changed.
b. Collections.reverse(list) returns a new list while the
original list is not changed.
c. Collections.sort(list) returns a new list while the
original list is not changed.
d. Collections.nCopies(int, Object) returns a new list that
consists of n copies of the object.
33. Which of the following is correct to create a list from
an array?
a. new List({"red", "green", "blue"})
b. new List(new String[]{"red", "green", "blue"})
c. Arrays.asList(new String[]{"red", "green", "blue"})
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d. new ArrayList(new String[]{"red", "green", "blue"})
e. new LinkedList(new String[]{"red", "green", "blue"})
34. Which of the following is correct to create a list from
an array?
a. new List({"red", "green", "blue"})
b. new List(new String[]{"red", "green", "blue"})
c. Arrays.asList(new String[]{"red", "green", "blue"})
d. new ArrayList(new String[]{"red", "green", "blue"})
e. new LinkedList(new String[]{"red", "green", "blue"})
35. To find a maximum object in an array of strings (e.g.,
String[] names = {"red", "green", "blue"}), use
a. Arrays.max(names)
b. Arrays.sort(names)
c. Collections.max(names)
d. Collections.max(Arrays.asList(names))
e. None of the above
36. To empty a Collection or a Map, you use the __________
method.
a.
empty
b.
clear
c.
zero
d.
setEmpty
37. Analyze the following code:
public class Test {
public static void main(String[] args) {
Map map = new HashMap();
map.put("123", "John Smith");
map.put("111", "George Smith");
map.put("123", "Steve Yao");
map.put("222", "Steve Yao");
}
}
a. After all the four entries are added to the map, "123"
is a key that corresponds to the value "John Smith".
b. After all the four entries are added to the map, "123"
is a key that corresponds to the value "Steve Yao".
c. After all the four entries are added to the map, "Steve
Yao" is a key that corresponds to the value "222".
d. After all the four entries are added to the map, "John
Smith" is a key that corresponds to the value "123".
e. A runtime error occurs because two entries with the same
key "123" are added to the map.
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Part II: Complete the following program.
1. (15 pts) Add the following new methods in BinaryTree.
/** Searches element o in this binary tree */
public boolean search(Object o)
/** Returns the depth of this binary tree. Depth is the
* number of the nodes in the longest path of the tree */
public int depth()
2 (15 pts)
Write a program that reads words from a text file and
displays all the nonduplicate words in ascending
order. The text file is passed as a command-line
argument.
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Key
Part I: Questions: (1 pts each)
1. Key:a
2. Key:b
3. Key:a
4. Key:d
5. Key:d
6. Key:b
7. Key:c
8. Key:b
9. Key:c
10. Key:a
11. Key:b
12. Key:d
13. Key:a
14. Key:d
15. Key:b
16. Key:a
17. Key:a
18. Key:a
19. Key:e
20. Key:b
21. Key:b
22. Key:c
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23. Key:e
24. Key:a
25. Key:a
26. Key:c
27. Key:d
28. Key:d
29. Key:b
30. Key:c
31. Key: b
32. Key:d
33. Key:c
34. Key:c
35. Key: d
36. Key:b
37. Key:b
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