Introduction to Java Programming, Seventh Edition, Y. Daniel Liang
Chapter 6 Arrays
Sections 6.2 Array Basics
1
What is the representation of the third element in an array called a?
A.
a[2]
B.
a(2)
C.
a[3]
D.
a(3)
2
If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, list[1] is ________.
A.
3.4
B.
2.0
C.
3.4
D.
5.5
E.
undefined
3
Which of the following is incorrect?
A.
int[] a = new int[2];
B.
int a[] = new int[2];
C.
int[] a = new int(2);
D.
int a = new int[2];
E.
int a() = new int[2];
4
If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, the highest index in array list is __________.
e, 4
A.
0
B.
1
C.
2
D.
3
5
How many elements are in array double[] list = new double[5]?
A.
4
B.
5
C.
6
D.
0
6
What is the correct term for numbers[99]?
A.
index
B.
index variable
C.
indexed variable
D.
array variable
E.
array
7
Suppose int i = 5, which of the following can be used as an index for array double[] t = new double[100]?
A.
i
B.
(int)(Math.random() * 100))
C.
i + 10
D.
i + 6.5
E.
Math.random() * 100
8
Analyze the following code.
public class Test {
public static void main(String[] args) {
int[] x = new int[3];
System.out.println("x[0] is " + x[0]);
}
}
A.
The program has a compile error because the size of the array wasn't specified when declaring the array.
B.
The program has a runtime error because the array elements are not initialized.
C.
The program runs fine and displays x[0] is 0.
D.
The program has a runtime error because the array element x[0] is not defined.
9
Which of the following statements is valid?
A.
int i = new int(30);
B.
double d[] = new double[30];
C.
int[] i = {3, 4, 3, 2};
D.
char[] c = new char();
E.
char[] c = new char[4]{'a', 'b', 'c', 'd'};
10
How can you initialize an array of two characters to 'a' and 'b'?
A.
char[] charArray = new char[2]; charArray = {'a', 'b'};
B.
char[2] charArray = {'a', 'b'};
C.
char[] charArray = {'a', 'b'};
D.
char[] charArray = new char[]{'a', 'b'};
11
What would be the result of attempting to compile and run the following code?
public class Test {
public static void main(String[] args) {
double[] x = new double[]{1, 2, 3};
System.out.println("Value is " + x[1]);
}
}
A.
The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by {1, 2, 3}.
B.
The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[3]{1, 2, 3};
C.
The program has a compile error because the syntax new double[]{1, 2, 3} is wrong and it should be replaced by new double[]{1.0, 2.0, 3.0};
D.
The program compiles and runs fine and the output "Value is 1.0" is printed.
E.
The program compiles and runs fine and the output "Value is 2.0" is printed.
12
Assume int[] t = {1, 2, 3, 4}. What is t.length?
A.
0
B.
3
C.
4
D.
5
13
Analyze the following code:
public class Test {
public static void main(String[] args) {
int[] x = new int[5];
int i;
for (i = 0; i < x.length; i++)
x[i] = i;
System.out.println(x[i]);
}
}
A.
The program displays 0 1 2 3 4.
B.
The program displays 4.
C.
The program has a runtime error because the last statement in the main method causes ArrayIndexOutOfBoundsException.
D.
The program has a compile error because i is not defined in the last statement in the main method.
14
(Tricky) What is output of the following code:
public class Test {
public static void main(String[] args) {
int[] x = {120, 200, 016};
for (int i = 0; i < x.length; i++)
System.out.print(x[i] + " ");
}
}
A.
120 200 16
B.
120 200 14
C.
120 200 20
D.
016 is a compile error. It should be written as 16.
Section 6.3 Copying Arrays
15
In the following code, what is the printout for list2?
class Test {
public static void main(String[] args) {
int[] list1 = {1, 2, 3};
int[] list2 = {1, 2, 3};
list2 = list1;
list1[0] = 0; list1[1] = 1; list2[2] = 2;
for (int i = 0; i < list2.length; i++)
System.out.print(list2[i] + " ");
}
}
A.
1 2 3
B.
1 1 1
C.
0 1 2
D.
0 1 3
16
In the following code, what is the printout for list1?
class Test {
public static void main(String[] args) {
int[] list1 = {1, 2, 3};
int[] list2 = {1, 2, 3};
list2 = list1;
list1[0] = 0; list1[1] = 1; list2[2] = 2;
for (int i = 0; i < list1.length; i++)
System.out.print(list1[i] + " ");
}
}
A.
1 2 3
B.
1 1 1
C.
0 1 2
D.
0 1 3
17
Analyze the following code:
public class Test {
public static void main(String[] args) {
int[] x = {1, 2, 3, 4};
int[] y = x;
x = new int[2];
for (int i = 0; i < y.length; i++)
System.out.print(y[i] + " ");
}
}
A.
The program displays 1 2 3 4
B.
The program displays 0 0
C.
The program displays 0 0 3 4
D.
The program displays 0 0 0 0
18
Analyze the following code:
public class Test {
public static void main(String[] args) {
int[] x = {1, 2, 3, 4};
int[] y = x;
x = new int[2];
for (int i = 0; i < x.length; i++)
System.out.print(x[i] + " ");
}
}
A.
The program displays 1 2 3 4
B.
The program displays 0 0
C.
The program displays 0 0 3 4
D.
The program displays 0 0 0 0
19
Analyze the following code:
public class Test {
public static void main(String[] args) {
final int[] x = {1, 2, 3, 4};
int[] y = x;
x = new int[2];
for (int i = 0; i < y.length; i++)
System.out.print(y[i] + " ");
}
}
A.
The program displays 1 2 3 4
B.
The program displays 0 0
C.
The program has a compile error on the statement x = new int[2], because x is final and cannot be changed.
D.
The elements in the array x cannot be changed, because x is final.
20
Analyze the following code.
int[] list = new int[5];
list = new int[6];
A.
The code has compile errors because the variable list cannot be changed once it is assigned.
B.
The code has runtime errors because the variable list cannot be changed once it is assigned.
C.
The code can compile and run fine. The second line assigns a new array to list.
D.
The code has compile errors because you cannot assign a different size array to list.
21
Analyze the following code:
public class Test {
public static void main(String[] args) {
int[] a = new int[4];
a[1] = 1;
a = new int[2];
System.out.println("a[1] is " + a[1]);
}
}
A.
The program has a compile error because new int[2] is assigned to a.
B.
The program has a runtime error because a[1] is not initialized.
C.
The program displays a[1] is 0.
D.
The program displays a[1] is 1.
22
The __________ method copies the sourceArray to the targetArray.
A.
System.copyArrays(sourceArray, 0, targetArray, 0, sourceArray.length);
B.
System.copyarrays(sourceArray, 0, targetArray, 0, sourceArray.length);
C.
System.arrayCopy(sourceArray, 0, targetArray, 0, sourceArray.length);
D.
System.arraycopy(sourceArray, 0, targetArray, 0, sourceArray.length);
Section 6.4 Passing Arrays to Methods
23
When you pass an array to a method, the method receives __________.
A.
a copy of the array
B.
a copy of the first element
C.
the reference of the array
D.
the length of the array
24
Show the output of the following code:
public class Test {
public static void main(String[] args) {
int[] x = {1, 2, 3, 4, 5};
increase(x);
int[] y = {1, 2, 3, 4, 5};
increase(y[0]);
System.out.println(x[0] + " " + y[0]);
}
public static void increase(int[] x) {
for (int i = 0; i < x.length; i++)
x[i]++;
}
public static void increase(int y) {
y++;
}
}
A.
0 0
B.
1 1
C.
2 2
D.
2 1
E.
1 2
25
Do the following two programs produce the same result?
Program I:
public class Test {
public static void main(String[] args) {
int[] list = {1, 2, 3, 4, 5};
reverse(list);
for (int i = 0; i < list.length; i++)
System.out.print(list[i] + " ");
}
public static void reverse(int[] list) {
int[] newList = new int[list.length];
for (int i = 0; i < list.length; i++)
newList[i] = list[list.length - 1 - i];
list = newList;
}
}
Program II:
public class Test {
public static void main(String[] args) {
int[] oldList = {1, 2, 3, 4, 5};
reverse(oldList);
for (int i = 0; i < oldList.length; i++)
System.out.print(oldList[i] + " ");
}
public static void reverse(int[] list) {
int[] newList = new int[list.length];
for (int i = 0; i < list.length; i++)
newList[i] = list[list.length - 1 - i];
list = newList;
}
}
A.
Yes
B.
No
26
Analyze the following code:
public class Test {
public static void main(String[] args) {
int[] oldList = {1, 2, 3, 4, 5};
reverse(oldList);
for (int i = 0; i < oldList.length; i++)
System.out.print(oldList[i] + " ");
}
public static void reverse(int[] list) {
int[] newList = new int[list.length];
for (int i = 0; i < list.length; i++)
newList[i] = list[list.length - 1 - i];
list = newList;
}
}
A.
The program displays 1 2 3 4 5.
B.
The program displays 1 2 3 4 5 and then raises an ArrayIndexOutOfBoundsException.
C.
The program displays 5 4 3 2 1.
D.
The program displays 5 4 3 2 1 and then raises an ArrayIndexOutOfBoundsException.
27
Analyze the following code:
public class Test1 {
public static void main(String[] args) {
xMethod(new double[]{3, 3});
xMethod(new double[5]);
xMethod(new double[3]{1, 2, 3});
}
public static void xMethod(double[] a) {
System.out.println(a.length);
}
}
A.
The program has a compile error because xMethod(new double[]{3, 3}) is incorrect.
B.
The program has a compile error because xMethod(new double[5]) is incorrect.
C.
The program has a compile error because xMethod(new double[3]{1, 2, 3}) is incorrect.
D.
The program has a runtime error because a is null.
28
The JVM stores the array in an area of memory, called _______, which is used for dynamic memory allocation where blocks of memory are allocated and freed in an arbitrary order.
A.
stack
B.
heap
C.
memory block
D.
dynamic memory
Section 6.5 Returning an Array from a Method
29
When you return an array from a method, the method returns __________.
A.
a copy of the array
B.
a copy of the first element
C.
the reference of the array
D.
the length of the array
30
Suppose a method p has the following heading:
public static int[] p()
What return statement may be used in p()?
A.
return 1;
B.
return {1, 2, 3};
C.
return int[]{1, 2, 3};
D.
return new int[]{1, 2, 3};
31
The reverse method is defined in the textbook. What is list1 after executing the following statements?
int[] list1 = {1, 2, 3, 4, 5, 6};
list1 = reverse(list1);
A.
list1 is 1 2 3 4 5 6
B.
list1 is 6 5 4 3 2 1
C.
list1 is 0 0 0 0 0 0
D.
list1 is 6 6 6 6 6 6
32
The reverse method is defined in this section. What is list1 after executing the following statements?
int[] list1 = {1, 2, 3, 4, 5, 6};
int[] list2 = reverse(list1);
A.
list1 is 1 2 3 4 5 6
B.
list1 is 6 5 4 3 2 1
C.
list1 is 0 0 0 0 0 0
D.
list1 is 6 6 6 6 6 6
Section 6.6 Variable-Length Argument Lists
33
Which of the following declarations are correct?
A.
public static void print(String... strings, double... numbers)
B.
public static void print(double... numbers, String name)
C.
public static double... print(double d1, double d2)
D.
public static void print(double... numbers)
E.
public static void print(int n, double... numbers)
34
Which of the following statements are correct to invoke the printMax method in Listing 6.5 in the book?
A.
printMax(1, 2, 2, 1, 4);
B.
printMax(new double[]{1, 2, 3});
C.
printMax(1.0, 2.0, 2.0, 1.0, 4.0);
D.
printMax(new int[]{1, 2, 3});
Section 6.7 Searching Arrays
35
For the binarySearch method in Section 6.7.2, what is low and high after the first iteration of the while loop when invoking binarySearch(new int[]{1, 4, 6, 8, 10, 15, 20}, 11)?
A.
low is 0 and high is 6
B.
low is 0 and high is 3
C.
low is 3 and high is 6
D.
low is 4 and high is 6
E.
low is 0 and high is 5
36
If a key is not in the list, the binarySearch method returns _________.
A.
insertion point
B.
insertion point - 1
C.
-(insertion point + 1)
D.
-insertion point
Section 6.8 Sorting Arrays
37
The selectionSort method is defined in this section. Assume list is {3.1, 3.1, 2.5, 6.4, 2.1}, what is the content of list after the first iteration of the outer loop in the method?
A.
3.1, 3.1, 2.5, 6.4, 2.1
B.
2.5, 3.1, 3.1, 6.4, 2.1
C.
2.1, 2.5, 3.1, 3.1, 6.4
D.
3.1, 3.1, 2.5, 2.1, 6.4
38
The selectionSort method is defined in this section. What is list1 after executing the following statements?
double[] list1 = {3.1, 3.1, 2.5, 6.4};
selectionSort(list1);
A.
list1 is 3.1, 3.1, 2.5, 6.4
B.
list1 is 2.5 3.1, 3.1, 6.4
C.
list1 is 6.4, 3.1, 3.1, 2.5
D.
list1 is 3.1, 2.5, 3.1, 6.4
Section 6.9 The Arrays Class
39
The __________ method sorts the array scores of the double[] type.
A.
java.util.Arrays(scores)
B.
java.util.Arrays.sorts(scores)
C.
java.util.Arrays.sort(scores)
D.
Njava.util.Arrays.sortArray(scores)
40
Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 30) return?
A.
0
B.
-1
C.
1
D.
2
E.
-2
41
Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 3) return?
A.
0
B.
-1
C.
1
D.
2
E.
-2
Section 6.10 Two-Dimensional Arrays
42
Which of the following statements are correct?
A.
char[][] charArray = {'a', 'b'};
B.
char[2][2] charArray = {{'a', 'b'}, {'c', 'd'}};
C.
char[2][] charArray = {{'a', 'b'}, {'c', 'd'}};
D.
char[][] charArray = {{'a', 'b'}, {'c', 'd'}};
43
Assume double[][] x = new double[4][5], what are x.length and x[2].length?
A.
4 and 4
B.
4 and 5
C.
5 and 4
D.
5 and 5
44
Analyze the following code:
public class Test {
public static void main(String[] args) {
boolean[][] x = new boolean[3][];
x[0] = new boolean[1]; x[1] = new boolean[2];
x[2] = new boolean[3];
System.out.println("x[2][2] is " + x[2][2]);
}
}
A.
The program has a compile error because new boolean[3][] is wrong.
B.
The program has a runtime error because x[2][2] is null.
C.
The program runs and displays x[2][2] is null.
D.
The program runs and displays x[2][2] is true.
E.
The program runs and displays x[2][2] is false.
45
Suppose a method p has the following heading:
public static int[][] p()
What return statement may be used in p()?
A.
return 1;
B.
return {1, 2, 3};
C.
return int[]{1, 2, 3};
D.
return new int[]{1, 2, 3};
E.
return new int[][]{{1, 2, 3}, {2, 4, 5}};
Section 6.11 Multidimensional Arrays
46
Assume double[][][] x = new double[4][5][6], what are x.length, x[2].length, and x[0][0].length?
A.
4, 5, and 6
B.
6, 5, and 4
C.
5, 5, and 5
D.
4, 5, and 4
47
Which of the following statements are correct?
A.
char[][][] charArray = new char[2][2][];
B.
char[2][2][] charArray = {'a', 'b'};
C.
char[][][] charArray = {{'a', 'b'}, {'c', 'd'}, {'e', 'f'}};
D.
char[][][] charArray = {{{'a', 'b'}, {'c', 'd'}, {'e', 'f'}}};