READ the
directions and answe r the followi ng question s below. B e sure to sho w your
wor k wherever necessary for PARTIAL CREDIT. This test will be graded out of 100 points.
True/ alse Questions (2 points e ch):
Decide whether he following state ents
are True or False.
1. A line ar
search is better for a n unsorted array
____True ______
2. Similar to
Arrays, ArrayLists can hold p rimitive an d reference types
______False____
3. The length of
an array can d ynamically change
__True________
4. Assum ing int[]
arr = {1, 2, 3} and int[ ] arr2
= {1, 2, 3}, determine the output for the f ollowing
line: arr == arr2
____False______
5. When an array of objects is c reated, the objects themselves ar e
also created
____True______
6. The fo llowing loop will go through every element i n an array c
alled arr:
for(int i = array.length – 1; i > 0; i--)
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ouble is
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_____false_____
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7.
An array of type
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reference type
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__false________
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8. The fo llowing pr
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gram will
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not run:
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___false_______
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Multiple Choice Questio s (3 poin ts each):
Select the best re sponse fo r the follo wing
question/stat ements. Be sure to circle your answer and write the let ter in
the space provided.
9. Deter mine the
values in the following a rray
__C________
in t[] arra y =
new int[5];
a) {0, 1, 2, 3,
4}
c) “0”
b) 0
d) n ull
10.
In w hich of the
f ollowing situations wo uld an Arr ayList b e more useful than an Array?
_____C_____
a) Storin g
primitive data
c) Array must be
able to chang e size
b) Storing
objects
d) Sorting data
11.
Sup pose an Ar ayList named list stored St ring objects. Which expression g ives the leng th
of the 3rd element l ist?
_______B___
a) list[2].length()
c) (String)(list[3].length())
b) l ist.get( d) l ist.get(
3).leng
2).leng
h()
h()
12. What is the value of count
after the fo llowing co de has been executed? ____A______
a) 2
b) 1
c) 0
d) 3
13. After
the following code is
executed, w hat
are the values in
array2?
____C___
a) {4, 3, 0, 0} b) {4, 1, 3, 0} c) {2, 4, 3, 0} d) {2, 4, 1, 3}
14. Whic h of the following stat ements is a
valid conclusion. Assu me that variable b is an array of k integers nd that the
following is true:
b[0 ] != b[k ] for al l k such such that 1 <= k
a) The value in b[0] does not occur anyw here else in
the array
___D_______
b) Array b is sorted
c) Array b is not sor ted
d) Array b contains no duplica tes
15. Whic h
sorting algorithm uses two sub arrays and only passes through t he array once?
___B_______
a) Selection
b) M
erge
c) Insertion
d) B inary
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a)
5
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b) 5.5
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c) 10
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d) 5.0
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Open‐ Ended Questions (6 points each):
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17.
Assume the arra y
arr
contains the following integers {34,
23, 67, 89, 12}. Write the values of the followi ng
expressi ons:
(a) arr 7%5] (b) arr[2] + arr[3]
(c) arr 2+3] (d) arr[arr[1]/6]
A = 67
B= 156
C = java.lang.ArrayIndexOutOfBoundsException
D= 89
18. Determine the
contents of t he two‐dim ensional a rray create d by the following code
ANS: Array bound exception
19.
Use nested loops
to create shown below.
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a
two‐dime nsional arr ay named array with the content s
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1
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1
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1
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1
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2
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4
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8
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16
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3
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9
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27
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81
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4
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16
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64
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256
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public static void
main(String[] args) {
int[][] values = {
{ 1, 1, 1,1 }, { 2, 4, 8,16 }, { 3, 9, 24,81 }, { 4, 16, 64,256 } };
for (int row = 0;
row <
4; row++) {
for (int col = 0;
col <
4; col++) {
System.out.print(values[row][col] + "
");
}
System.out.println();
}
}
}
Use the resource class below to answer questions 20‐24
20. (a) Create an ar ray named people of type Pers n of
length 2
public class
Person {
public static void
main(String[] args) {
Person people[]=new
Person[2];
}
}
(b) C reate an A rayList named list of
type P erson
public class
Person {
public static void
main(String[] args) {
Person people[]=new
Person[2];
ArrayList<Person>
list=new ArrayList<Person>();
}
}
21. (a) W hat is the c urrent valu e of the elements in th e people?
[null,
null]
(b) hat
is the current val e of the ele ments in th e list?
[]
22. (a) Set the 2nd
el ement in people as a
Person n amed Ricky who is 17
Person people[]=new
Person[2];
people[1].name="Rickey";
people[1].age=17;
(b) O utput the age of 2nd el ement in p ople
Person people[]=new
Person[2];
people[1].name="Rickey";
people[1].age=17;
people[0].name="Naresh";
people[0].age=20;
System.out.println(people[1].name);
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Fred
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22
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Austin
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12
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Person
p1=new
Person("Fred",22);
Person p2=new
Person("Austin",12);
ArrayList<Person>
list = new
ArrayList<Person>();
list.add(p1);
list.add(p2);
(b) Output the name of 1st element in list
System.out.println("Names
: " + list.get(1).getName()+ " Age : " + list.get(1).getAge());
24. Use an enhanced for loop to print the names and ages of each Person in list
package com.pratice;
import java.util.ArrayList;
import java.util.Arrays;
public class Person {
String name;
int age;
public
Person(String name, int age) {
this.name
= name;
this.age
= age;
}
public String
getName() {
return
name;
}
public void
setName(String name) {
this.name
= name;
}
public int
getAge() {
return
age;
}
public void
setAge(int age) {
this.age
= age;
}
public static
void main(String[] args) {
Person
people[]=new Person[2];
people[1].name="Rickey";
people[1].age=17;
people[0].name="Naresh";
people[0].age=20;
Person
p1=new Person("Fred",22);
Person
p2=new Person("Austin",12);
ArrayList<Person>
list = new ArrayList<Person>();
list.add(p1);
list.add(p2);
for(int
i=0;i<list.size();i++){
System.out.println("Names
: " + list.get(i).getName()+ " Age : " + list.get(i).getAge());
}
}
}
25. Show contents of the array after each pass of the outer loop in
the (ascending)
selection sort algorithm
15 42 72 25 31 35
package com.pratice;
import java.util.ArrayList;
import java.util.Arrays;
class SelectionSort {
void
sort(int arr[]) {
int
n = arr.length;
for
(int i = 0; i < n - 1; i++) {
int
min_idx = i;
for
(int j = i + 1; j < n; j++)
if
(arr[j] < arr[min_idx])
min_idx
= j;
int
temp = arr[min_idx];
arr[min_idx]
= arr[i];
arr[i]
= temp;
}
}
void
printArray(int arr[]) {
int
n = arr.length;
for
(int i = 0; i < n; ++i)
System.out.print(arr[i]
+ " ");
System.out.println();
}
public
static void main(String args[]) {
SelectionSort
ob = new SelectionSort();
int
arr[] = { 1542, 72, 25, 31, 35 };
ob.sort(arr);
System.out.println("Sorted
array");
ob.printArray(arr);
}
}
26.
Write a method
named removeA() that accepts an ArrayList of character values and removes any letter
A’s from the list (Assume the list is
LOWERCASE)
package
com.pratice;
import java.util.ArrayList;
import java.util.Arrays;
import
java.util.Iterator;
public class
Person {
public static void
main(String args[]) {
ArrayList<String>
list = new
ArrayList<String>();
list.add("suresh");
list.add("ram");
list.add("naresh");
Iterator<String>
it = list.iterator();
while (it.hasNext())
{
String
element = it.next();
if (element.contains(Character.toString('a'))) {
list.remove(element);
}
}
}
}
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