One-dimensional arrays in Java - Practice Problems & Coding Challenges

trophy

Challenge - 5 Problems

💻 code output

intermediate

Output of array element modification

What is the output of this Java code snippet?

Java

public class Main {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        arr[2] = arr[0] + arr[4];
        System.out.println(arr[2]);
    }
}

A 8

B 3

C 5

D 6

💻 code output

intermediate

Sum of array elements

What is the output of this Java program?

Java

public class Main {
    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40};
        int sum = 0;
        for (int i = 0; i < numbers.length; i++) {
            sum += numbers[i];
        }
        System.out.println(sum);
    }
}

A 100

B 10

C 40

D 90

🔧 debug

advanced

Identify the error in array access

What error does this Java code produce when run?

Java

public class Main {
    public static void main(String[] args) {
        int[] arr = new int[3];
        arr[3] = 10;
        System.out.println(arr[3]);
    }
}

A SyntaxError

B NullPointerException

C ArrayIndexOutOfBoundsException

D No error, prints 10

💻 code output

advanced

Output after array element swap

What is the output of this Java program?

Java

public class Main {
    public static void main(String[] args) {
        int[] arr = {7, 8, 9};
        int temp = arr[0];
        arr[0] = arr[2];
        arr[2] = temp;
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }
}

A 9 8 7

B 7 8 9

C 8 7 9

D 9 7 8

🧠 conceptual

expert

Number of elements after array initialization

How many elements does the array contain after this declaration?

int[] arr = new int[5];

A 0

B 5

C 6

D 4