Array declaration and initialization in Java - Practice Problems & Coding Challenges

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Challenge - 5 Problems

💻 code output

intermediate

Output of array initialization and access

What is the output of the following Java code?

Java

public class Main {
    public static void main(String[] args) {
        int[] numbers = new int[3];
        numbers[0] = 5;
        numbers[1] = 10;
        numbers[2] = 15;
        System.out.println(numbers[1]);
    }
}

A 0

B 5

C 10

D 15

💻 code output

intermediate

Output of array initialization with values

What will be printed by this Java program?

Java

public class Main {
    public static void main(String[] args) {
        String[] fruits = {"Apple", "Banana", "Cherry"};
        System.out.println(fruits.length);
    }
}

A 3

B 2

C 0

D Compilation error

💻 code output

advanced

Output of multi-dimensional array initialization

What is the output of this Java code?

Java

public class Main {
    public static void main(String[] args) {
        int[][] matrix = new int[2][3];
        matrix[0][1] = 7;
        matrix[1][2] = 9;
        System.out.println(matrix[1][2] + matrix[0][1]);
    }
}

A ArrayIndexOutOfBoundsException

B 79

C 0

D 16

💻 code output

advanced

Output of array default values

What will this Java program print?

Java

public class Main {
    public static void main(String[] args) {
        boolean[] flags = new boolean[4];
        System.out.println(flags[2]);
    }
}

A true

B false

C null

D Compilation error

🧠 conceptual

expert

Number of elements in a jagged array

Consider the following Java code snippet. How many elements does the jagged array contain in total?

Java

public class Main {
    public static void main(String[] args) {
        int[][] jagged = new int[3][];
        jagged[0] = new int[2];
        jagged[1] = new int[4];
        jagged[2] = new int[3];
    }
}

A 9

B 7

C 3

D 12