Using Libraries In Our Code

java.util.Arrays

Let's move on to practice, and as an example, we will use the library java.util.Arrays. We can see that the parent library is java, followed by the child library util, and then the specific library we need, Arrays.

Main

import java.util.Arrays;


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import java.util.Arrays;

We have already mentioned this library in the course on arrays when discussing array methods. Now, let's see how we can use these methods in code using an example:

Main

package com.example;

// do not modify the code below this comment

// importing Arrays library into our code

import java.util.Arrays;

public class Main {

public static void main(String[] args) {

// creating an int array with some unsorted values

int[] array = {1, 5, 6, 2, 0, -4, 2};

// using Arrays library to sort our elements

Arrays.sort(array);

// printing each element from the sorted array to the console

for (int element : array) {

System.out.print(element + " ");

}


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package com.example;

// do not modify the code below this comment

// importing Arrays library into our code
import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        // creating an int array with some unsorted values
        int[] array = {1, 5, 6, 2, 0, -4, 2};  
        // using Arrays library to sort our elements
        Arrays.sort(array);  
        // printing each element from the sorted array to the console
        for (int element : array) {  
            System.out.print(element + " ");
        }
    }
}

Let's go through the code written above.

We import the necessary library and use a class from that library to call its sorting method. You can see the syntax of how we use it: ClassName.methodName(array);. You can also see that the sorted array is printed in the console, with values displayed from smallest to largest. The method we imported from the Arrays library handled the sorting.

Let's also take a look at another method from Arrays - fill.

Main

package com.example;

// do not modify the code below this comment

// importing Arrays library into our code

import java.util.Arrays;

public class Main {

public static void main(String[] args) {

// creating an int array with some different values

int[] array = {1, 5, 6, 2, 0, -4, 2};

// using Arrays library to fill the array with the value "1"

Arrays.fill(array, 1);

// printing each element from the filled array to the console

for (int element : array) {

System.out.print(element + " ");

}


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package com.example;

// do not modify the code below this comment

// importing Arrays library into our code
import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        // creating an int array with some different values
        int[] array = {1, 5, 6, 2, 0, -4, 2};  
        // using Arrays library to fill the array with the value "1"
        Arrays.fill(array, 1);  
        // printing each element from the filled array to the console
        for (int element : array) {  
            System.out.print(element + " ");
        }
    }
}

We have the same integer array, but we're not sorting it this time. Instead, we're replacing each element of the array with a specified value. Notice that we first specify the array we want to fill in the parentheses, and then we provide the value with which we want to fill the array.

After all the operations, you can see that the array displayed on the screen consists of all elements equal to 1.

Tarefa

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