Question 1

Consider the following code snippet: ArrayList arrList = new ArrayList(); For (int i = 0; i < arrList.size(); i++) { ArrList.add(i + 3); } What value is stored in the element of the array list at index 0? A) 0 B) 3 C) 6 D) None

Accepted Answer

The answer of Consider the following code snippet:
ArrayList<Integer> arrList =...

Question 2

Consider the following code snippet: ArrayList somedata = new ArrayList(); Somedata.add(10.5); What is the size of the array list somedata after the given code snippet is executed? A) 0 B) 1 C) 10 D) 2

Accepted Answer

The size of the ArrayList somedata is 1 after executing the given code snippet because only one element (10.5) has been added to it.

Question 3

Your program needs to store a sequence of integers of unknown length. Which of the following is most suitable to use? A) An array declared as int[] marks; B) A array list declared as ArrayList marks = new ArrayList(); C) An array declared as int marks[10000]; D) An array declared as int marks[10];

Accepted Answer

An ArrayList allows for dynamic sizing, meaning that it can adjust its size based on the number of integers being stored. This is useful when the length of the sequence is unknown. Additionally, an ArrayList provides convenient methods for adding, removing, and accessing elements in the sequence.

Question 4

What is the value of the cnt variable after the execution of the code snippet below? ArrayList somenum = new ArrayList(); Somenum.add(1); Somenum.add(2); Somenum.add(1); Int cnt = 0; For (int index = 0; index < somenum.size(); index++) { If (somenum.get(index) % 2 == 0) { Cnt++; } } A) 1 B) 2 C) 3 D) 0

Accepted Answer

The answer of What is the value of the cnt...

Question 5

What is the result of the following definition of an array list?
ArrayList<Double> points;
A) The statement causes a compile time error as the size of the array list is not defined.
B) The statement creates an array list of size 0.
C) The statement creates an array list with unlimited size.
D) The statement defines an array list reference but leaves its value as null.

Accepted Answer

The statement defines an ArrayList reference but does not initialize the reference to an object. Therefore, the value of the ArrayList is null.

Question 6

Consider the following code snippet:
Public static void check(ArrayList<Integer> chknum1)
{
Int cnt = 0;
For(int i = 0; i < chknum1.size(); i++)
{
If(chknum1.get(i) == 0)
{
Cnt++;
}
}
System.out.println("The total 0 values in the list are: " + cnt);
}
Which one of the following is true about the check method in the given code snippet?
A) The check method counts all the elements with value 0 in an array list passed as a parameter to the method.
B) The check method removes all the elements with value 0 from an array list passed as a parameter to the method.
C) The check method counts all the elements with value 0 in an array list passed as a parameter to a method and also returns the count.
D) The check method adds 0 to the elements of an array list as a parameter to a method and also returns the array list.

Accepted Answer

The check method iterates through the given ArrayList and counts all the elements with a value of 0. It does not remove any elements, return the count or modify the original ArrayList in any way.

Question 7

Consider the following line of code for calling a method named func1: Func1(listData, varData); Which one of the following method headers is valid for func1, where listData is an integer array list and varData is an integer variable? A) public static void func1(int[] listData, int varData) B) public static void func1(ArrayList listData, varData) C) public static void func1(ArrayList ldata, int vdata) D) public static void func1(int vdata, ArrayList ldata)

Accepted Answer

The method header C correctly matches the types and order of the arguments: an ArrayList of Integers and an integer variable.

Question 8

What is the value of myArray[1][2] after this code snippet is executed?
Int count = 0;
Int[][] myArray = new int[4][5];
For (int i = 0; i < 5; i++)
{
For (int j = 0; j < 4; j++)
{
MyArray[j][i] = count;
Count++;
}
}
A) 8
B) 9
C) 19
D) 11

Accepted Answer

The code iterates through each element of the 2D array and assigns it a value starting from 0 and incrementing by 1 for each element. Since we are interested in the value at index [1][2] (second row, third column), we can calculate its value as follows:
- The outer loop iterates through columns (5 iterations). When i = 2 (third column), the inner loop (j) has 2 iterations (j=0, j=1). Therefore, elements at index [0][2] and [1][2] have already been assigned values (in the second iteration of the outer loop).
- When i = 2 and j = 1, count is incremented to 9 and assigned to myArray[1][2]. Therefore, the answer is B) 9.

Question 9

Consider the following code snippet:
Int[][] arr =
{
{ 1, 2, 3 },
{ 4, 5, 6 }
};
Int val = arr[0][2] + arr[1][2];
System.out.println(val);
What is the output of the given code snippet on execution?
A) 5
B) 7
C) 9
D) 10

Accepted Answer

The answer of Consider the following code snippet:
Int[][] arr =
{
{...

Question 10

Which one of the following is the correct code snippet for calculating the largest value in an integer array list arrList of size 10? A) int maximum = 0; For (int counter = 1; counter < arrList.size(); counter++) { If (arrList.get(counter) > maximum) { Maximum = arrList.get(counter); } } B) int maximum = arrList.get(0); For (int counter = 1; counter < arrList.size(); counter++) { If (arrList.get(counter) > maximum) { Maximum = arrList.get(counter); } } C) int maximum = arrList.get(1); For (int counter = 1; counter < arrList.size(); counter++) { If (arrList.get(counter) > maximum) { Maximum = arrList.get(counter); } } D) int maximum = arrList.get(0); For (int counter = 1; counter > arrList.size(); counter++) { If (arrList.get(counter) < maximum) { Maximum = arrList.get(counter); } }

Accepted Answer

This code snippet initializes the maximum value as the first element in the array list and then iterates through the rest of the list, comparing each element to the current maximum and updating it if a larger value is found. This approach correctly handles the case where all values in the array list are negative, since the initial maximum value is a valid value in the array list.

Question 11

What is the output of the following code snippet?
ArrayList<Integer> num;
Num)add(4);
System.out.println(num.size());
A) 1
B) 0
C) 4
D) Error because num is not initialized

Accepted Answer

The answer of What is the output of the following...

Question 12

Which one of the following is a correct declaration for a method named passAList that has as arguments an array list myList of size 10 and an integer array intArr of size 20, and that modifies the contents of myList and intArr? A) public static void passAList(ArrayList myList(10), int[] intArr) B) public static void passAList(ArrayList myList, int[20] intArr) C) public static void passAList(ArrayList myList, int[] intArr) D) public static void passAList(ArryaList myList, int intArr)

Accepted Answer

The correct declaration for the method "passAList" would be "public static void passAList(ArrayList<Integer> myList, int[] intArr)" as it correctly specifies the parameters as an ArrayList of integers and an integer array, without specifying their size. Option A and B include incorrect syntax for declaring an ArrayList and an array size, respectively. Option D has a typo in the word "ArrayList".

Question 13

What should you check for when calculating the largest value in an array list?
A) The array list contains at least one element.
B) The array list contains at least two elements.
C) The array list contains the minimum value in the first element.
D) The array list contains the maximum value in the first element.

Accepted Answer

To calculate the largest value in an array list, it's essential to ensure that the array list contains at least one element. Without any elements, it's impossible to determine a largest value, making this check crucial. The number of elements beyond one, or the specific values in any positions (including the first), are not necessary conditions for the process of finding the largest value.

Question 14

Which one of the following is a correct declaration for a method named passAList with the array list num of size 5 as a parameter? A) public static void passAList(ArrayList num[5]) B) public static void passAList(ArrayList num, 5) C) public static void passAList(ArrayList num) D) public static void passAList(num)

Accepted Answer

Option A is incorrect because the array size cannot be specified in the method parameter declaration.
Option B is incorrect because the comma should not be used in the parameter declaration and also the size of the ArrayList cannot be specified.
Option D is incorrect because it does not specify the type and name of the parameter.
Hence, option C is the correct declaration for the method named passAList with the ArrayList num of size 5 as a parameter.

Question 15

Which one of the following statements about declaring an array list as a method parameter is true?
A) An array list declared as a method parameter should be accompanied with its size.
B) An array list declared as a method parameter is a constant value by default.
C) An array list value cannot be modified in a method when the array list is declared as a parameter.
D) An array list value can be modified inside the method.

Accepted Answer

An array list value can be modified inside the method when declared as a parameter. This is because the array list passed as a parameter is essentially a reference to the original array list, allowing the method to modify its values.

Question 16

Which one of the following is a valid signature of a method with an integer two-dimensional array parameter of size 10 x 10?
A) public static void func(int[][] arr)
B) public static void func(int[10][] arr)
C) public static void func(int[][10] arr)
D) public static void func(int[10][10] arr)

Accepted Answer

Option A is the correct signature for a method with an integer two-dimensional array parameter of size 10 x 10. The parameter is declared as int[][] arr, meaning an array of integers with two dimensions. The size of each dimension is not specified as it can vary.

Question 17

Consider the following code snippet:
Int val = arr[0][2];
Which value of arr is stored in the val variable?
A) The value in the first row and the second column
B) The value in the first row and the first column
C) The value in the first row and the third column
D) The value in the third row and the second column

Accepted Answer

Since the code is accessing the element with index [0][2], it means the first row and the third column of the array. Therefore, the value in the first row and the third column of the array will be stored in the val variable.

Question 18

Which one of the following code snippets accepts the integer input in an array list named num1 and stores the even integers of num1 in another array list named evennum? A) ArrayList num1 = new ArrayList(); ArrayList evennum = new ArrayList(); Scanner in = new Scanner(System.in); Int data; For (int i = 0; i < 10; i++) { Data = in.nextInt(); Num1.add(data); If (num1.get(i) % 2 == 0) { Evennum.add(num1.get(i)); } } B) ArrayList num1 = new ArrayList(); ArrayList evennum = new ArrayList(); Scanner in = new Scanner(System.in); Int data; For (int i = 0; i < 10; i++) { Data = in.nextInt(); Num1.add(data); If (num1.get(i) % 2 != 0) { Evennum.add(num1.get(i)); } } C) ArrayList num1 = new ArrayList(); ArrayList evennum = new ArrayList(); Scanner in = new Scanner(System.in); Int data; For int i = 0; i < 10; i++) { Data = in.nextInt(); Num1.add(data); If (num1.get(i) % 2 != 0) { Evennum[i] = num1[i]; } } D) ArrayList num1 = new ArrayList(); ArrayList evennum = new ArrayList(); Scanner in = new Scanner(System.in); Int data; For (int i = 0; i < 10; i++) { Data = in.nextInt(); Num1.add(data); If (num1.get(i) % 2 == 0) { Evennum[i] = num1[i]; } }

Accepted Answer

Code snippet A correctly initializes two array lists, num1 and evennum, and uses a for loop to accept integer inputs from the user and add them to num1. It then checks each integer in num1 to see if it is even, and adds it to evennum if it is. The other code snippets either add odd integers to evennum or attempt to use array indexing on array lists, which is not possible.

Question 19

What is the output of the following code snippet? Public static int check(ArrayList listData) { Int sum = 0; For (int i = 0; i < listData.size(); i++) { Sum = sum + listData.get(i); } Return sum; } Public static void main(String[] args) { ArrayList vdata = new ArrayList(); Int rsum; For (int cnt = 0; cnt < 3; cnt++) { Vdata.add(cnt + 1); } Rsum = check(vdata); System.out.println(rsum); } A) 4 B) 2 C) 3 D) 6

Accepted Answer

The check method takes an ArrayList of integers as input and returns the sum of all values in the list.

In the main method, an ArrayList vdata is created and populated with the values 1, 2, and 3. Then, the check method is called with vdata as the argument, and the returned value is stored in rsum.

Since the sum of 1, 2, and 3 is 6, the output of the program will be 6. Therefore, the correct option is D.

Question 20

Consider the following code snippet: ArrayList num1 = new ArrayList(); Int data; Scanner in = new Scanner(System.in); For (int i = 0; i < 5; i++) { Data = in.nextInt(); Num1.add(data); If (data == 0 && num1.size() > 3) { Num1.remove(num1.size() - 1); } } System.out.println("size is : " + num1.size()); What is the output of the given code snippet if the user enters 1,2,0,0,1 as the input? A) size is : 1 B) size is : 2 C) size is : 4 D) size is : 0

Accepted Answer

The ArrayList num1 will contain the values {1,2,0,0,1} after the for loop. The if condition is true when the input value is 0 and the size of num1 is greater than 3. This means that the last element of num1 will be removed if the input value is 0 and there are at least 4 elements in num1. Therefore, the final contents of num1 will be {1,2,0,1} and the size of num1 will be 4.

Quiz 6: Arrays and Arraylists

Consider the following code snippet: ArrayList<Integer> arrList = new ArrayList<Integer>() ; For (int i = 0; i < arrList.size() ; i++) { ArrList.add(i + 3) ; } What value is stored in the element of the array list at index 0?

Consider the following code snippet: ArrayList<Double> somedata = new ArrayList<Double>() ; Somedata.add(10.5) ; What is the size of the array list somedata after the given code snippet is executed?

Your program needs to store a sequence of integers of unknown length. Which of the following is most suitable to use?

What is the result of the following definition of an array list? ArrayList<Double> points;

Consider the following line of code for calling a method named func1: Func1(listData, varData) ; Which one of the following method headers is valid for func1, where listData is an integer array list and varData is an integer variable?

What is the value of myArray[1][2] after this code snippet is executed? Int count = 0; Int[][] myArray = new int[4][5]; For (int i = 0; i < 5; i++) { For (int j = 0; j < 4; j++) { MyArray[j][i] = count; Count++; } }

Consider the following code snippet: Int[][] arr = { { 1, 2, 3 }, { 4, 5, 6 } }; Int val = arr[0][2] + arr[1][2]; System.out.println(val) ; What is the output of the given code snippet on execution?

Which one of the following is the correct code snippet for calculating the largest value in an integer array list arrList of size 10?

What is the output of the following code snippet? ArrayList<Integer> num; Num) add(4) ; System.out.println(num.size() ) ;

Which one of the following is a correct declaration for a method named passAList that has as arguments an array list myList of size 10 and an integer array intArr of size 20, and that modifies the contents of myList and intArr?

What should you check for when calculating the largest value in an array list?

Which one of the following is a correct declaration for a method named passAList with the array list num of size 5 as a parameter?

Which one of the following statements about declaring an array list as a method parameter is true?

Which one of the following is a valid signature of a method with an integer two-dimensional array parameter of size 10 x 10?

Consider the following code snippet: Int val = arr[0][2]; Which value of arr is stored in the val variable?

Which one of the following code snippets accepts the integer input in an array list named num1 and stores the even integers of num1 in another array list named evennum?