Array -Java Programming MCQ Questions and Answers

31

In Java arrays are

A) objects B) object references C) primitive data type D) None of the above

Discuss

Answer & Solution

Answer: Option A

Solution:

In java an array is a container object that holds a fixed number of values of a single type. The length of an array is established when the array is created. After creation, its length is fixed.

32

Which one of the following is a valid statement?

A) char[] c = new char(); B) char[] c = new char[5]; C) char[] c = new char(4); D) char[] c = new char[];

Discuss

Answer & Solution

Answer: Option B

Solution:

The syntax for declaring and creating an array variable in java is:
dataType[] arrayRefVar = new dataType[arraySize];

Thus, option (A) and option (C) is syntactically wrong as parentheses( ( ) ) is used instead of square brackets( [ ] ).
Option (D) is incorrect as the size of the array is missing.

33

What is the result of compiling and running the following code?

public class Test{
        public static void main(String[] args){
                int[] a = new int[0];
                System.out.print(a.length);
        }
}

A) 0 B) Compilation error, arrays cannot be initialized to zero size. C) Compilation error, it is a.length() not a.length D) None of the above

Discuss

Answer & Solution

Answer: Option A

Solution:

Step 1:
Declare a public class named Test.

Step 2:
Define the main method with the public and static modifiers and a parameter of type String array named args.

Step 3:
Declare an array variable a of type int[].

Step 4:
Initialize the array a with a size of 0 using the new keyword.

Step 5:
Print the length of the array a using the length property.

Therefore, when you compile and run the code, the output will be:
0

This output corresponds to the length of the array a, which is 0.

34

What will be the output?

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.

Discuss

Answer & Solution

Answer: Option C

Solution:

Program is syntactically correct, so no error.
In java, if the array is not initialized at the time of declaration and creation then all the elements of the array are initialized to 0 by default.

35

What is the output of the following code?

public class Test{
        public static void main(String args[]){
                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);
        }
}

A) 0 B) 1 C) 2 D) 3 E) 4

Discuss

Answer & Solution

Answer: Option B

Solution:

In the given program.
Line 7 : if(myList[i] > max) execute only on time when i =1;
when i = 1 then myList[i] = 5 and max = 1(so the statement is true and if block will be executed).
Then, max = myList[i] = 5 and indexOfMax = i = 1.
After that if statement always false. so indexOfMax value remain 1.

Therefore the value of indexOfMax is 1 at end of the for loop.

36

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) 120 200 016 D) 016 is a compile error. It should be written as 16.

Discuss

Answer & Solution

Answer: Option B

Solution:

016 is an octal number. The prefix 0 indicates that a number is in octal.

37

Determine output:

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(y[i] + " ");
        }
}

A) 1 2 3 4 B) 0 0 0 0 C) 1 2 D) 0 0 E) None of these

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

38

Analyze the following code and choose the correct answer.

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

A) The code has compile errors because the variable arr cannot be changed once it is assigned. B) The code has runtime errors because the variable arr cannot be changed once it is assigned. C) The code can compile and run fine. The second line assigns a new array to arr. D) The code has compile errors because we cannot assign a different size array to arr.

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

39

What will be the output?

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] B) The program has a runtime error because a[1] = null C) a[1] is 0 D) a[1] is 1

Discuss

Answer & Solution

Answer: Option C

Solution:

After executing the statement a = new int[2], a refers to int[2]. The default value for a[0] and a[1] is 0.

40

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.

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board