Array Methods

Part of the Fundamentals section of Coddy's Java journey — lesson 61 of 73.

Arrays are packed with many methods (functionalities). To access a method, write:

Arrays.methodName(arrayName, otherParameters)

Here is a list of the basic methods:

fill(array, value) - fills the array with a specific value

toString() - converts the array to a string

sort(array) - sorts the array in ascending order

equals(array1, array2) - compares two arrays to determine if they are equal

Here is an example of how to use the fill method with toString:

int[] numbers = new int[5];
Arrays.fill(numbers, 10);
System.out.println(Arrays.toString(numbers));

This will output [10, 10, 10, 10, 10].

Example of the sort method:

int[] numbers = {5, 2, 9, 1, 5, 6};
Arrays.sort(numbers);
System.out.println(Arrays.toString(numbers));

This will output [1, 2, 5, 5, 6, 9].

Challenge

Easy

Create a method named merge that receives two arrays as arguments. The method merges the two arrays into one sorted array and returns it.

Important: The final merged array must be sorted in ascending order.

For example the following arguments: merge(new String[] {"1", "4", "2"}, new String[] {"2", "5", "9"}) will return ["1", "2", "2", "4", "5", "9"] (notice the result is sorted)

Use System.arraycopy() to copy elements from one array to another. The syntax is:

System.arraycopy(sourceArray, sourceStartPosition, destinationArray, destinationStartPosition, length)

For example:

// Source array
String[] sourceArray = {"1", "2", "3", "4", "5"};
        
// Destination array
String[] destinationArray = new String[5];
        
// Copy elements from sourceArray to destinationArray
System.arraycopy(sourceArray, 0, destinationArray, 0, 5);

Destination array after copy: 1 2 3 4 5

Cheat sheet

Arrays class provides useful methods for array manipulation:

Arrays.methodName(arrayName, otherParameters)

Basic Arrays methods:

fill(array, value) - fills the array with a specific value
toString(array) - converts the array to a string
sort(array) - sorts the array in ascending order
equals(array1, array2) - compares two arrays to determine if they are equal

Example using fill and toString:

int[] numbers = new int[5];
Arrays.fill(numbers, 10);
System.out.println(Arrays.toString(numbers)); // [10, 10, 10, 10, 10]

Example using sort:

int[] numbers = {5, 2, 9, 1, 5, 6};
Arrays.sort(numbers);
System.out.println(Arrays.toString(numbers)); // [1, 2, 5, 5, 6, 9]

Use System.arraycopy() to copy elements between arrays:

System.arraycopy(sourceArray, sourceStartPosition, destinationArray, destinationStartPosition, length)

Example:

String[] sourceArray = {"1", "2", "3", "4", "5"};
String[] destinationArray = new String[5];
System.arraycopy(sourceArray, 0, destinationArray, 0, 5);

Try it yourself

import java.util.Arrays;
import java.util.Scanner;


public class Main {
    public static String[] merge(String[] arr1, String[] arr2) {
        // Write code here
        return null;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String textArr1 = scanner.nextLine();
        String textArr2 = scanner.nextLine();
        String[] arr1 = textArr1.split(",");
        String[] arr2 = textArr2.split(",");

        String[] mergedArray = merge(arr1, arr2);
        System.out.println(Arrays.toString(mergedArray));
    }
}