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Joshua Villy
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ch_8

Frage 1 von 47

1

What is the representation of the third element in an array called a?

Wähle eine der folgenden:

  • a[2]

  • a(2)

  • a[3]

  • a(3)

Erklärung

Frage 2 von 47

1

If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, list[1] is ________.

Wähle eine der folgenden:

  • 3.4

  • 2.0

  • 3.5

  • 5.5

  • undefined

Erklärung

Frage 3 von 47

1

If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, the highest index in array list is __________.

Wähle eine der folgenden:

  • 0

  • 1

  • 2

  • 3

  • 4

Erklärung

Frage 4 von 47

1

How many elements are in array double[] list = new double[5]?

Wähle eine der folgenden:

  • 4

  • 5

  • 6

  • 0

Erklärung

Frage 5 von 47

1

What is the correct term for numbers[99]?

Wähle eine der folgenden:

  • index

  • index variable

  • indexed variable

  • array variable

  • array

Erklärung

Frage 6 von 47

1

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]);
}
}

Wähle eine der folgenden:

  • The program has a compile error because the size of the array wasn't specified when declaring the array.

  • The program has a runtime error because the array elements are not initialized.

  • The program runs fine and displays x[0] is 0.

  • The program has a runtime error because the array element x[0] is not defined.

Erklärung

Frage 7 von 47

1

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]);
}
}

Wähle eine der folgenden:

  • 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}.

  • 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};

  • 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};

  • The program compiles and runs fine and the output "Value is 1.0" is printed.

  • The program compiles and runs fine and the output "Value is 2.0" is printed.

Erklärung

Frage 8 von 47

1

Assume int[] t = {1, 2, 3, 4}. What is t.length?

Wähle eine der folgenden:

  • 0

  • 3

  • 4

  • 5

Erklärung

Frage 9 von 47

1

What is the output of the following code?

double[] myList = {1, 5, 5, 5, 5, 1};
double max = myList[0];
int indexOfMax = 0;
for (int i = 1; i < myList.length; i++) {
if (myList[i] > max) {
max = myList[i];
indexOfMax = i;
}
}
System.out.println(indexOfMax);

Wähle eine der folgenden:

  • 0

  • 1

  • 2

  • 3

  • 4

Erklärung

Frage 10 von 47

1

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]);
}
}

Wähle eine der folgenden:

  • The program displays 0 1 2 3 4.

  • The program displays 4.

  • The program has a runtime error because the last statement in the main method causes ArrayIndexOutOfBoundsException.

  • The program has a compile error because i is not defined in the last statement in the main method.

Erklärung

Frage 11 von 47

1

(for-each loop) Analyze the following code:

public class Test {
public static void main(String[] args) {
double[] x = {2.5, 3, 4};
for (double value: x)
System.out.print(value + " ");
}
}

Wähle eine der folgenden:

  • The program displays 2.5, 3, 4

  • The program displays 2.5 3 4

  • The program displays 2.5 3.0 4.0

  • The program displays 2.5, 3.0 4.0

  • The program has a syntax error because value is undefined.

Erklärung

Frage 12 von 47

1

hat is the output of the following code?

int[] myList = {1, 2, 3, 4, 5, 6};

for (int i = myList.length - 2; i >= 0; i--) {
myList[i + 1] = myList[i];
}

for (int e: myList)
System.out.print(e + " ");

Wähle eine der folgenden:

  • 1 2 3 4 5 6

  • 6 1 2 3 4 5

  • 6 2 3 4 5 1

  • 1 1 2 3 4 5

  • 2 3 4 5 6 1

Erklärung

Frage 13 von 47

1

(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] + " ");
}
}

Wähle eine der folgenden:

  • 120 200 16

  • 120 200 14

  • 120 200 20

  • 016 is a compile error. It should be written as 16.

Erklärung

Frage 14 von 47

1

What is output of the following code:

public class Test {
public static void main(String[] args) {
int list[] = {1, 2, 3, 4, 5, 6};

for (int i = 1; i < list.length; i++)
list[i] = list[i - 1];

for (int i = 0; i < list.length; i++)
System.out.print(list[i] + " ");
}
}

Wähle eine der folgenden:

  • 1 2 3 4 5 6

  • 2 3 4 5 6 6

  • 2 3 4 5 6 1

  • 1 1 1 1 1 1

Erklärung

Frage 15 von 47

1

What will be displayed by the following code?

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] + " ");
}
}

Wähle eine der folgenden:

  • 1 2 3

  • 1 1 1

  • 0 1 2

  • 0 1 3

Erklärung

Frage 16 von 47

1

What will be displayed by the following code?

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] + " ");
}
}

Wähle eine der folgenden:

  • 123

  • 111

  • 012

  • 013

Erklärung

Frage 17 von 47

1

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] + " ");
}
}

Wähle eine der folgenden:

  • The program displays 1 2 3 4

  • The program displays 0 0

  • The program displays 0 0 3 4

  • The program displays 0 0 0 0

Erklärung

Frage 18 von 47

1

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] + " ");
}
}

Wähle eine der folgenden:

  • The program displays 1 2 3 4

  • The program displays 0 0

  • The program displays 0 0 3 4

  • The program displays 0 0 0 0

Erklärung

Frage 19 von 47

1

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] + " ");
}
}

Wähle eine der folgenden:

  • The program displays 1 2 3 4

  • The program displays 0 0

  • The program has a compile error on the statement x = new int[2], because x is final and cannot be changed.

  • The elements in the array x cannot be changed, because x is final.

Erklärung

Frage 20 von 47

1

Analyze the following code.

int[] list = new int[5];
list = new int[6];

Wähle eine der folgenden:

  • The code has compile errors because the variable list cannot be changed once it is assigned.

  • The code has runtime errors because the variable list cannot be changed once it is assigned.

  • The code can compile and run fine. The second line assigns a new array to list.

  • The code has compile errors because you cannot assign a different size array to list.

Erklärung

Frage 21 von 47

1

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]);
}
}

Wähle eine der folgenden:

  • The program has a compile error because new int[2] is assigned to a.

  • The program has a runtime error because a[1] is not initialized.

  • The program displays a[1] is 0.

  • The program displays a[1] is 1.

Erklärung

Frage 22 von 47

1

The __________ method copies the sourceArray to the targetArray.

Wähle eine der folgenden:

  • System.copyArrays(sourceArray, 0, targetArray, 0, sourceArray.length);

  • System.copyarrays(sourceArray, 0, targetArray, 0, sourceArray.length);

  • System.arrayCopy(sourceArray, 0, targetArray, 0, sourceArray.length);

  • System.arraycopy(sourceArray, 0, targetArray, 0, sourceArray.length);

Erklärung

Frage 23 von 47

1

When you pass an array to a method, the method receives __________.

Wähle eine der folgenden:

  • a copy of the array

  • a copy of the first element

  • the reference of the array

  • the length of the array

Erklärung

Frage 24 von 47

1

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++;
}
}

Wähle eine der folgenden:

  • 0 0

  • 1 1

  • 2 2

  • 2 1

  • 1 2

Erklärung

Frage 25 von 47

1

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;
}
}

Wähle eine der folgenden:

  • yes

  • no

Erklärung

Frage 26 von 47

1

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;
}
}

Wähle eine der folgenden:

  • The program displays 1 2 3 4 5.

  • The program displays 1 2 3 4 5 and then raises an ArrayIndexOutOfBoundsException.

  • The program displays 5 4 3 2 1.

  • The program displays 5 4 3 2 1 and then raises an ArrayIndexOutOfBoundsException.

Erklärung

Frage 27 von 47

1

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);
}
}

Wähle eine der folgenden:

  • The program has a compile error because xMethod(new double[]{3, 3}) is incorrect.

  • The program has a compile error because xMethod(new double[5]) is incorrect.

  • The program has a compile error because xMethod(new double[3]{1, 2, 3}) is incorrect.

  • The program has a runtime error because a is null.

Erklärung

Frage 28 von 47

1

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.

Wähle eine der folgenden:

  • stack

  • heap

  • memory block

  • dynamic memory

Erklärung

Frage 29 von 47

1

When you return an array from a method, the method returns __________.

Wähle eine der folgenden:

  • a copy of the array

  • a copy of the first element

  • the reference of the array

  • the length of the array

Erklärung

Frage 30 von 47

1

Suppose a method p has the following heading:

public static int[] p()

What return statement may be used in p()?

Wähle eine der folgenden:

  • return 1;

  • return {1, 2, 3};

  • return int[]{1, 2, 3};

  • return new int[]{1, 2, 3};

Erklärung

Frage 31 von 47

1

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);

Wähle eine der folgenden:

  • list1 is 1 2 3 4 5 6

  • list1 is 6 5 4 3 2 1

  • list1 is 0 0 0 0 0 0

  • list1 is 6 6 6 6 6 6

Erklärung

Frage 32 von 47

1

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);

Wähle eine der folgenden:

  • list1 is 1 2 3 4 5 6

  • list1 is 6 5 4 3 2 1

  • list1 is 0 0 0 0 0 0

  • list1 is 6 6 6 6 6 6

Erklärung

Frage 33 von 47

1

For the binarySearch method in Section 6.9.2, 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)?

Wähle eine der folgenden:

  • low is 0 and high is 6

  • low is 0 and high is 3

  • low is 3 and high is 6

  • low is 4 and high is 6

  • low is 0 and high is 5

Erklärung

Frage 34 von 47

1

If a key is not in the list, the binarySearch method returns _________.

Wähle eine der folgenden:

  • insertion point

  • insertion point - 1

  • -(insertion point + 1)

  • -insertion point

Erklärung

Frage 35 von 47

1

Use the selectionSort method presented in this section to answer this question. 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?

Wähle eine der folgenden:

  • 3.1, 3.1, 2.5, 6.4, 2.1

  • 2.5, 3.1, 3.1, 6.4, 2.1

  • 2.1, 2.5, 3.1, 3.1, 6.4

  • 3.1, 3.1, 2.5, 2.1, 6.4

  • 2.1, 3.1, 2.5, 6.4, 3.1

Erklärung

Frage 36 von 47

1

Use the selectionSort method presented in this section to answer this question. What is list1 after executing the following statements?

double[] list1 = {3.1, 3.1, 2.5, 6.4};
selectionSort(list1);

Wähle eine der folgenden:

  • list1 is 3.1, 3.1, 2.5, 6.4

  • list1 is 2.5 3.1, 3.1, 6.4

  • list1 is 6.4, 3.1, 3.1, 2.5

  • list1 is 3.1, 2.5, 3.1, 6.4

Erklärung

Frage 37 von 47

1

The __________ method sorts the array scores of the double[] type.

Wähle eine der folgenden:

  • java.util.Arrays(scores)

  • java.util.Arrays.sorts(scores)

  • java.util.Arrays.sort(scores)

  • Njava.util.Arrays.sortArray(scores)

Erklärung

Frage 38 von 47

1

Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 30) return?

Wähle eine der folgenden:

  • 0

  • -1

  • 1

  • 2

  • -2

Erklärung

Frage 39 von 47

1

Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 3) return?

Wähle eine der folgenden:

  • 0

  • -1

  • 1

  • 2

  • -2

Erklärung

Frage 40 von 47

1

Assume int[] list1 = {3, 4, 1, 9, 13}, int[] list2 = {3, 4, 1, 9, 13}, and int[] list3 = {4, 3, 1, 9, 13}, what is

System.out.println(java.util.Arrays.equals(list1, list2)
+ " " + java.util.Arrays.equals(list1, list3));

Wähle eine der folgenden:

  • true true

  • true false

  • false true

  • false fasle

Erklärung

Frage 41 von 47

1

Assume int[] scores = {3, 4, 1, 9, 13}, which of the following statement displays all the element values in the array?

Wähle eine der folgenden:

  • System.out.println(scores);

  • System.out.println(scores.toString());

  • System.out.println(java.util.Arrays.toString(scores));

  • System.out.println(scores[0]);

Erklärung

Frage 42 von 47

1

Which of the following is incorrect?

Wähle eine oder mehr der folgenden:

  • int a[] = new int[2];

  • int[] a = new int(2);

  • int a = new int[2];

  • int a() = new int[2];

  • int[] a = new int[2];

Erklärung

Frage 43 von 47

1

Suppose int i = 5, which of the following can be used as an index for array double[] t = new double[100]?

Wähle eine oder mehr der folgenden:

  • i

  • (int)(Math.random() * 100))

  • i + 10

  • i + 6.5

  • Math.random() * 100

Erklärung

Frage 44 von 47

1

Which of the following statements is valid?

Wähle eine oder mehr der folgenden:

  • int i = new int(30);

  • double d[] = new double[30];

  • int[] i = {3, 4, 3, 2};

  • char[] c = new char();

  • char[] c = new char[4]{'a', 'b', 'c', 'd'};

Erklärung

Frage 45 von 47

1

How can you initialize an array of two characters to 'a' and 'b'?

Wähle eine oder mehr der folgenden:

  • char[] charArray = new char[2]; charArray = {'a', 'b'};

  • char[2] charArray = {'a', 'b'};

  • char[] charArray = {'a', 'b'};

  • char[] charArray = new char[]{'a', 'b'};

Erklärung

Frage 46 von 47

1

Which of the following declarations are correct?

Wähle eine oder mehr der folgenden:

  • public static void print(String... strings, double... numbers)

  • public static void print(double... numbers, String name)

  • public static double... print(double d1, double d2)

  • public static void print(double... numbers)

  • public static void print(int n, double... numbers)

Erklärung

Frage 47 von 47

1

Which of the following statements are correct to invoke the printMax method in Listing 6.5 in the textbook?

Wähle eine oder mehr der folgenden:

  • printMax(1, 2, 2, 1, 4);

  • printMax(new double[]{1, 2, 3});

  • printMax(1.0, 2.0, 2.0, 1.0, 4.0);

  • printMax(new int[]{1, 2, 3});

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