Question

JAVA LANGUAGE

1. What is the value of creditScores.length, if you have declared an array as follows: int[] creditScores = {670, 720, 815};?

a. 0 b. 1

c. 2 d. 3

2. Which of the following correctly assigns the value 100 to each of the array element? Assume the array is declared as int [] num = new int[4]

a. for(x=0;x<3;++x) num[x]=100;

c. for(x=1;x<4;++x) num[x]=100 ; 3. Consider the following code fragment

int[][] rectangle = new int[4][2]; What is the size of this array?

a. 4

b. for(x=0;x<4;++x) num[x]=100; d. for(x=1;x<5;++x) num[x]=100 ;

b. 8

d.10

c.6

4. Which of the following data type can be used as the data type of an array subscript? a. character b. double

c. int d. String

5. What is the value of num[2], If you declare an integer array as follows,?

int[] num = {101, 202, 303, 404, 505, 606};

a. 101 b. 202

c. 303 d. impossible to tell

6. How do you indicate the final element of the array, if you declare an array as follows?

int [] num = new int[6];

a. num[0] b. num[6] c.num[5] d. impossible

1. Write the statements for the following operations based on an array Num and method sum. Assume the

array is declared as double [] Num = new int[5];

a. Call the method sum by passing the data Num to the method

b. Declare the method sum appropriately; assume that the method returns the result back to main.

2. Declare an array named NUM of ten elements of type int and initialize the elements to the values 10 , 20 , ..., 100 respectively.

3. Differentiate length field and length() method by illustrating appropriate example. (4 Marks : 2 marks for correct definition of the field and method + 2 marks for correct illustration of example)

4. Write a statement that declares an array named Marks that contains exactly 25 elements of type

double.

5. Given an array A = {3, 7, 8, 5}. What will be in array A after running the given function

Evaluate (4, A)   

public void Evaluate(int n, int B[])

{

int k;

for(k = 0; k < n; k++)

Answer 1

1.

What is the value of creditScores.length, if you have declared an array as follows: int[] creditScores = {670, 720, 815};?

a. 0 b. 1

c. 2 d. 3

Ans: Option (d) 3

when we use arr.length it gives the total number of elements in the array.

So, creditScores.length gives 3 since there are 3 elements in the creditScores[]

2.

Which of the following correctly assigns the value 100 to each of the array element? Assume the array is declared as int [] num = new int[4]

a. for(x=0;x<3;++x) num[x]=100;

b. for(x=0;x<4;++x) num[x]=100;

c. for(x=1;x<4;++x) num[x]=100 ;

d. for(x=1;x<5;++x) num[x]=100 ;

Ans: Option (b) for(x=0; x<4; ++x) num[x]=100 ;

The index of array starts from 0 . Here the size of array is 4. So the indexes are 0,1,2,3.

So the for loop should run from x=0 to x<4.and assign num[x] = 100;

So, option b is correct

3.

Consider the following code fragment

int[][] rectangle = new int[4][2]; What is the size of this array?

a. 4

b. 8

c.6

d.10

Ans: Option (b) 8

There are 4 rows and 2 columns in this array. So, the size of this array is 4*2 = 8

4.

Which of the following data type can be used as the data type of an array subscript?

a. character b. double

c. int d. String

Ans:Option (c) int

Suppose if we need to access an element in 1st row(index starts from 0) and 2nd column(index starts from 0) in a 2d array M. Then we use the indexes.

M[0][1].

So, here the indexes are of type int.

5.

What is the value of num[2], If you declare an integer array as follows,?

int[] num = {101, 202, 303, 404, 505, 606};

a. 101 b. 202

c. 303 d. impossible to tell

Ans: Option (c) 303

Since the index starts from 0

num[0] = 101

num[1] = 202

num[2] = 303

num[3] = 404

num[4] = 505

num[5] = 606

6.

How do you indicate the final element of the array, if you declare an array as follows?

int [] num = new int[6];

a. num[0] b. num[6] c.num[5] d. impossible

Ans: Option (c) num[5]

If n is the size of an array then the final element in the array is at position n-1

Given the size of num array is 6

Therefore the final element in the array is num[6-1] = num[5]

1.

Write the statements for the following operations based on an array Num and method sum. Assume the

array is declared as double [] Num = new int[5];

a. Call the method sum by passing the data Num to the method

Ans:

In the above array it is declared in a wrong way. The datatype in the left side and right side are not equal.

So, we should convert eithere double to int or int to double and call the sum() method

I am converting it as an int array

so double [] Num = new int[5];

To call the sum method we should call like the following

sum(Num);

b. Declare the method sum appropriately; assume that the method returns the result back to main.

Ans:

public static int sum(int[] Num)
{
    int n = Num.length;
    int x = 0;
    for(int i = 0; i<n; i++)
    {
        x = x+Num[i];
    }
    return(x);
}

Total code with call method and method declaration:

public class Main
{
    public static void main(String[] args) {
        int[] Num = new int[5];
        int res = sum(Num);
        System.out.println(res);
    }


    public static int sum(int[] Num)
    {
        int n = Num.length;
        int x = 0;
        for(int i = 0; i<n; i++)
        {
            x = x+Num[i];
        }
        return(x);
    }
}

Here since the elements of array is not initialized they will be initialized automatically to 0.

SO, the sum method will return 0.

2.

Declare an array named NUM of ten elements of type int and initialize the elements to the values 10 , 20 , ..., 100 respectively.

Ans:

Array can be initialized like this

int[] Num = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};

or

int[] Num = new int[]{10, 20, 30, 40, 50, 60, 70, 80, 90, 100};

3.

Differentiate length field and length() method by illustrating appropriate example. (4 Marks : 2 marks for correct definition of the field and method + 2 marks for correct illustration of example)

length:

length is a final variable which is used to get the length of an array using syntax arrayname,length

length() is a final variable which is used for string variables. It gives the length of string by using the syntax

stringname.length();

For eg:

int[] Num = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};

Num.length gives result 10 since there are 10 elements in the Num array

String s = "Hello";

s.length(); gives result as 5 since there are 5 characters in the above string s

Code:

public class Main {
    public static void main(String[] args) {
        int[] Num = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
        int n1 = Num.length;
        String s = "Hello";
        int n2 = s.length();
        System.out.println("length of Num array: " + n1);
        System.out.println("length of string s: " + n2);
    }
}

O/P:

length of Num array: 10
length of string s: 5

4.

Write a statement that declares an array named Marks that contains exactly 25 elements of type

double.

Ans:

Here the size is 25 and the type is double. So the array will be declared as

double[] Marks = new double[25]

5.

Given an array A = {3, 7, 8, 5}. What will be in array A after running the given function

Evaluate (4, A)   

public void Evaluate(int n, int B[])

{

int k;

for(k =0;k<n;k++)

System.out.println(B[i]);

}

Ans:

It prints all the elements in the array B

So the result will be

3

7

8

5

(Reupload the last question q5. The last lines are missing in the question))

(I thought it is print statement. If its not print reupload it or write it in comments I will solve.))

(If you still have any doubts regarding the answer please comment I will definitely help).