standard-library-in-x

Notes and readings for STL workshop


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sort()

Function

It is used to sort the elements present in the specified list of Collection in ascending order using the Merge Sort technique.

It can sort the elements of ArrayList, linked list, queue and many more. It can be used to sort an array after creating an ArrayList of given array items.

Declaration

public static <T> void sort(List<T> list,Comparator<? super T> c)	

Parameters

list - This is the list to be sorted.

c - This is the comparator to determine the order of the list.

Example (Using a Comparator)

import java.util.*;
import java.lang.*;
import java.io.*;

class Product
{
    int id, weight;
    String name;
    public Product(int id, String name, int weight)
    {
        this.id = id;
        this.weight = weight;
        this.name = name;
    }
 
    public String toString()
    {
        return this.id + " " + this.name +
                           " " + this.weight;
    }
}
 
class SortbyWeight implements Comparator<Product>
{
    // Used for sorting in ascending order of weight
    public int compare(Product p1, Product p2)
    {
        return p1.weight - p2.weight;
    }
}
 
public class SortUsingComparator
{
    public static void main (String args[])
    {
        ArrayList<Product> list = new ArrayList<Product>();
        list.add(new Product(111, "Watermelon",3));
        list.add(new Product(112, "Cake",2));
        list.add(new Product(113, "Chocolate",1));
 
        System.out.println("Unsorted");
        for (Product p:list)
            System.out.println(p);
 
        Collections.sort(list, new SortbyWeight());
 
        System.out.println("\nSorted by weight");
        for (Product p:list)
            System.out.println(p);
    }
}

Output

Unsorted
111 Watermelon 3
112 Cake 2
113 Chocolate 1

Sorted by weight
113 Chocolate 1
112 Cake 2
111 Watermelon 3