4049255
Beschreibung
Quiz von Joshua Villy, aktualisiert more than 1 year ago
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Erstellt von Joshua Villy
vor etwa 9 Jahre
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Frage 1
Frage
What is the representation of the third element in an array called a?
Antworten
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a[2]
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a(2)
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a[3]
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a(3)
Frage 2
Frage
If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, list[1] is ________.
Antworten
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3.4
-
2.0
-
3.5
-
5.5
-
undefined
Frage 3
Frage
If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, the highest index in array list is __________.
Antworten
-
0
-
1
-
2
-
3
-
4
Frage 4
Frage
How many elements are in array double[] list = new double[5]?
Antworten
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4
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5
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6
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0
Frage 5
Frage
What is the correct term for numbers[99]?
Antworten
-
index
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index variable
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indexed variable
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array variable
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array
Frage 6
Frage
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]);
}
}
Antworten
-
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.
Frage 7
Frage
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]);
}
}
Antworten
-
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.
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The program compiles and runs fine and the output "Value is 2.0" is printed.
Frage 8
Frage
Assume int[] t = {1, 2, 3, 4}. What is t.length?
Antworten
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0
-
3
-
4
-
5
Frage 9
Frage
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);
Antworten
-
0
-
1
-
2
-
3
-
4
Frage 10
Frage
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]);
}
}
Antworten
-
The program displays 0 1 2 3 4.
-
The program displays 4.
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The program has a runtime error because the last statement in the main method causes ArrayIndexOutOfBoundsException.
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The program has a compile error because i is not defined in the last statement in the main method.
Frage 11
Frage
(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 + " ");
}
}
Antworten
-
The program displays 2.5, 3, 4
-
The program displays 2.5 3 4
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The program displays 2.5 3.0 4.0
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The program displays 2.5, 3.0 4.0
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The program has a syntax error because value is undefined.
Frage 12
Frage
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 + " ");
Antworten
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1 2 3 4 5 6
-
6 1 2 3 4 5
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6 2 3 4 5 1
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1 1 2 3 4 5
-
2 3 4 5 6 1
Frage 13
Frage
(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] + " ");
}
}
Antworten
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120 200 16
-
120 200 14
-
120 200 20
-
016 is a compile error. It should be written as 16.
Frage 14
Frage
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] + " ");
}
}
Antworten
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1 2 3 4 5 6
-
2 3 4 5 6 6
-
2 3 4 5 6 1
-
1 1 1 1 1 1
Frage 15
Frage
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] + " ");
}
}
Antworten
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1 2 3
-
1 1 1
-
0 1 2
-
0 1 3
Frage 16
Frage
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] + " ");
}
}
Antworten
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123
-
111
-
012
-
013
Frage 17
Frage
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] + " ");
}
}
Antworten
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The program displays 1 2 3 4
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The program displays 0 0
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The program displays 0 0 3 4
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The program displays 0 0 0 0
Frage 18
Frage
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] + " ");
}
}
Antworten
-
The program displays 1 2 3 4
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The program displays 0 0
-
The program displays 0 0 3 4
-
The program displays 0 0 0 0
Frage 19
Frage
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] + " ");
}
}
Antworten
-
The program displays 1 2 3 4
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The program displays 0 0
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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.
Frage 20
Frage
Analyze the following code.
int[] list = new int[5];
list = new int[6];
Antworten
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The code has compile errors because the variable list cannot be changed once it is assigned.
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The code has runtime errors because the variable list cannot be changed once it is assigned.
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The code can compile and run fine. The second line assigns a new array to list.
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The code has compile errors because you cannot assign a different size array to list.
Frage 21
Frage
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]);
}
}
Antworten
-
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.
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The program displays a[1] is 0.
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The program displays a[1] is 1.
Frage 22
Frage
The __________ method copies the sourceArray to the targetArray.
Antworten
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System.copyArrays(sourceArray, 0, targetArray, 0, sourceArray.length);
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System.copyarrays(sourceArray, 0, targetArray, 0, sourceArray.length);
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System.arrayCopy(sourceArray, 0, targetArray, 0, sourceArray.length);
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System.arraycopy(sourceArray, 0, targetArray, 0, sourceArray.length);
Frage 23
Frage
When you pass an array to a method, the method receives __________.
Antworten
-
a copy of the array
-
a copy of the first element
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the reference of the array
-
the length of the array
Frage 24
Frage
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++;
}
}
Antworten
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0 0
-
1 1
-
2 2
-
2 1
-
1 2
Frage 25
Frage
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;
}
}
Antworten
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yes
-
no
Frage 26
Frage
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;
}
}
Antworten
-
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.
Frage 27
Frage
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);
}
}
Antworten
-
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.
Frage 28
Frage
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.
Antworten
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stack
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heap
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memory block
-
dynamic memory
Frage 29
Frage
When you return an array from a method, the method returns __________.
Antworten
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a copy of the array
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a copy of the first element
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the reference of the array
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the length of the array
Frage 30
Frage
Suppose a method p has the following heading:
public static int[] p()
What return statement may be used in p()?
Antworten
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return 1;
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return {1, 2, 3};
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return int[]{1, 2, 3};
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return new int[]{1, 2, 3};
Frage 31
Frage
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);
Antworten
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list1 is 1 2 3 4 5 6
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list1 is 6 5 4 3 2 1
-
list1 is 0 0 0 0 0 0
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list1 is 6 6 6 6 6 6
Frage 32
Frage
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);
Antworten
-
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
Frage 33
Frage
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)?
Antworten
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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
Frage 34
Frage
If a key is not in the list, the binarySearch method returns _________.
Antworten
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insertion point
-
insertion point - 1
-
-(insertion point + 1)
-
-insertion point
Frage 35
Frage
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?
Antworten
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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
Frage 36
Frage
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);
Antworten
-
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
Frage 37
Frage
The __________ method sorts the array scores of the double[] type.
Antworten
-
java.util.Arrays(scores)
-
java.util.Arrays.sorts(scores)
-
java.util.Arrays.sort(scores)
-
Njava.util.Arrays.sortArray(scores)
Frage 38
Frage
Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 30) return?
Antworten
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0
-
-1
-
1
-
2
-
-2
Frage 39
Frage
Assume int[] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 3) return?
Antworten
-
0
-
-1
-
1
-
2
-
-2
Frage 40
Frage
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));
Antworten
-
true true
-
true false
-
false true
-
false fasle
Frage 41
Frage
Assume int[] scores = {3, 4, 1, 9, 13}, which of the following statement displays all the element values in the array?
Antworten
-
System.out.println(scores);
-
System.out.println(scores.toString());
-
System.out.println(java.util.Arrays.toString(scores));
-
System.out.println(scores[0]);
Frage 42
Frage
Which of the following is incorrect?
Antworten
-
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];
Frage 43
Frage
Suppose int i = 5, which of the following can be used as an index for array double[] t = new double[100]?
Antworten
-
i
-
(int)(Math.random() * 100))
-
i + 10
-
i + 6.5
-
Math.random() * 100
Frage 44
Frage
Which of the following statements is valid?
Antworten
-
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'};
Frage 45
Frage
How can you initialize an array of two characters to 'a' and 'b'?
Antworten
-
char[] charArray = new char[2]; charArray = {'a', 'b'};
-
char[2] charArray = {'a', 'b'};
-
char[] charArray = {'a', 'b'};
-
char[] charArray = new char[]{'a', 'b'};
Frage 46
Frage
Which of the following declarations are correct?
Antworten
-
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)
Frage 47
Frage
Which of the following statements are correct to invoke the printMax method in Listing 6.5 in the textbook?
Antworten
-
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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