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sort() method is a java.util.Arrays class method.
Syntax:
public static void sort(int[] arr, int from_Index, int to_Index) arr - the array to be sorted from_Index - the index of the first element, inclusive, to be sorted to_Index - the index of the last element, exclusive, to be sorted This method doesn't return any value.
A Java program to sort an array of integers in ascending order.
Java
// A sample Java program to sort an array of integers// using Arrays.sort(). It by default sorts in// ascending orderimport java.util.Arrays;public class SortExample{ public static void main(String[] args) { // Our arr contains 8 elements int[] arr = {13, 7, 6, 45, 21, 9, 101, 102}; Arrays.sort(arr); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Output:
Modified arr[] : [6, 7, 9, 13, 21, 45, 101, 102]
We can also use sort() to sort a subarray of arr[]
Java
// A sample Java program to sort a subarray// using Arrays.sort().import java.util.Arrays;public class SortExample{ public static void main(String[] args) { // Our arr contains 8 elements int[] arr = {13, 7, 6, 45, 21, 9, 2, 100}; // Sort subarray from index 1 to 4, i.e., // only sort subarray {7, 6, 45, 21} and // keep other elements as it is. Arrays.sort(arr, 1, 5); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Output:
Modified arr[] : [13, 6, 7, 21, 45, 9, 2, 100]
We can also sort in descending order.
Java
// A sample Java program to sort a subarray// in descending order using Arrays.sort().import java.util.Arrays;import java.util.Collections;public class SortExample{ public static void main(String[] args) { // Note that we have Integer here instead of // int[] as Collections.reverseOrder doesn't // work for primitive types. Integer[] arr = {13, 7, 6, 45, 21, 9, 2, 100}; // Sorts arr[] in descending order Arrays.sort(arr, Collections.reverseOrder()); System.out.printf("Modified arr[] : %s", Arrays.toString(arr)); }} |
Output:
Modified arr[] : [100, 45, 21, 13, 9, 7, 6, 2]
We can also sort strings in alphabetical order.
Java
// A sample Java program to sort an array of strings// in ascending and descending orders using Arrays.sort().import java.util.Arrays;import java.util.Collections;public class SortExample{ public static void main(String[] args) { String arr[] = {"practice.geeksforgeeks.org", "quiz.geeksforgeeks.org", "code.geeksforgeeks.org" }; // Sorts arr[] in ascending order Arrays.sort(arr); System.out.printf("Modified arr[] : \n%s\n\n", Arrays.toString(arr)); // Sorts arr[] in descending order Arrays.sort(arr, Collections.reverseOrder()); System.out.printf("Modified arr[] : \n%s\n\n", Arrays.toString(arr)); }} |
Output:
Modified arr[] : Modified arr[] : [quiz.geeksforgeeks.org, practice.geeksforgeeks.org, code.geeksforgeeks.org]
We can also sort an array according to user defined criteria.
We use Comparator interface for this purpose. Below is an example.
Java
// Java program to demonstrate working of Comparator// interfaceimport java.util.*;import java.lang.*;import java.io.*;// A class to represent a student.class Student{ int rollno; String name, address; // Constructor public Student(int rollno, String name, String address) { this.rollno = rollno; this.name = name; this.address = address; } // Used to print student details in main() public String toString() { return this.rollno + " " + this.name + " " + this.address; }}class Sortbyroll implements Comparator<Student>{ // Used for sorting in ascending order of // roll number public int compare(Student a, Student b) { return a.rollno - b.rollno; }}// Driver classclass Main{ public static void main (String[] args) { Student [] arr = {new Student(111, "bbbb", "london"), new Student(131, "aaaa", "nyc"), new Student(121, "cccc", "jaipur")}; System.out.println("Unsorted"); for (int i=0; i<arr.length; i++) System.out.println(arr[i]); Arrays.sort(arr, new Sortbyroll()); System.out.println("\nSorted by rollno"); for (int i=0; i<arr.length; i++) System.out.println(arr[i]); }} |
Output:
Unsorted 111 bbbb london 131 aaaa nyc 121 cccc jaipur Sorted by rollno 111 bbbb london 121 cccc jaipur 131 aaaa nyc
Arrays.sort() vs Collections.sort()
Arrays.sort works for arrays which can be of primitive data type also. Collections.sort() works for objects Collections like ArrayList, LinkedList, etc.
This article is contributed by Mohit Gupta. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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