Java Program to Find the Third Largest Number in an Array

In the previous article, we have seen Java Program to Find the Difference between the Sum of Even and Odd Elements in an Array

In this article we are going to see how we can find the third largest element in an array.

Java Program to Find the Third Largest Number in an Array

Array is a data structure which stores a fixed size sequential collection of values of single type. Where with every array elements/values memory location is associated. Each array elements have it’s own index where array index starts from 0.

In Array set of variables referenced by a single variable name and it’s array index position. It is also called as a container object which contains elements of similar type.

Declaration of an array:

dataType[] arrayName; (or)                              //Declaring an array
dataType []arrayName; (or)
dataType arr[];

Instantiation of an Array:

arrayName = new datatype[size];                    //Allocating memory to array

Combining both Statements in One:

dataType[] arrayName = new dataType[size] //Declaring and Instantiating array

Initialization of an Array:

arrayName[index-0]= arrayElement1             //Initializing the array

...

arrayName[index-s]= arrayElementS

Combining all Statements in One:

dataType arrayName[ ]={e1,e2,e3};               //declaration, instantiation and initialization

Let’s see different ways to find the third largest element in an array.

Method-1: Java Program to Find the Third Smallest Number in an Array By Comparing Elements

Approach:

  • Take an array with elements in it.
  • Print the array elements.
  • Create a variable and store the first element of the array in it.
  • Compare the variable with the whole array to find and store the largest element.
  • Repeat the above step for the array elements except the largest element to find out the second largest element.
  • Similarly repeat the step for third largest element and print it.

Program:

import java.util.*;
public class Main
{
    public static void main(String args[])
    {
        // Creating the array
        int arr[] = {12, 2, 34, 20, 54, 6};

        // Initializing the first element of the array to large
        int large=arr[0];        
        
        // Compares all the element to find out the largest one
        for(int i:arr)
        {
            if(large<i)
                large=i;
        }

        // Initializing the first element of the array to secondLarge
        int secondLarge=arr[0];        
        
        // Compares all the element to find out the second largest one
        for(int i:arr)
        {
            if(secondLarge<i&&i!=large)
                secondLarge=i;
        }

        // Initializing the first element of the array to thirdLarge
        int thirdLarge=arr[0];        
        
        // Compares all the element to find out the third largest one
        for(int i:arr)
        {
            if(thirdLarge<i&&i!=large&&i!=secondLarge)
                thirdLarge=i;
        }

        // Prints the array elements
        printArray(arr);
        
        // Prints the third largest element
        System.out.println("The third largest element of the array is: "+thirdLarge);
    }

    // Function to print the array
    static void printArray(int arr[])
    {
        System.out.println("The array elements are");
        for(int i = 0; i < arr.length ; i++)
            System.out.print(arr[i]+" ");
        System.out.println();
    }
}


Output:

The array elements are
12 2 34 20 54 6 
The third largest element of the array is: 20

Method-2: Java Program to Find the Third Smallest Number in an Array By Using Sorting

Approach:

  • Take an array with elements in it.
  • Print the array elements.
  • Use function Arrays.sort() to sort the array in ascending order.
  • Print the third last element.

Program:

import java.util.*;
public class Main
{
    public static void main(String args[])
    {
        // Creating the array
        int arr[] = {12, 2, 34, 20, 54, 6};
        
        // Prints the array elements
        printArray(arr);
        
        // Sorts the array in ascending order
        Arrays.sort(arr);

        
        
        // Prints the third largest element
        System.out.println("The third largest element of the array is: "+arr[arr.length-3]);
    }

    // Function to print the array
    static void printArray(int arr[])
    {
        System.out.println("The array elements are");
        for(int i = 0; i < arr.length ; i++)
            System.out.print(arr[i]+" ");
        System.out.println();
    }
}

Output:

The array elements are
12 2 34 20 54 6 
The third largest element of the array is: 20

Method-3: Java Program to Find the Third Smallest Number in an Array By Using ArrayList and collections

Approach:

  • Take an array with elements in it.
  • Print the array elements.
  • Convert the array elements into a list.
  • Use the Collection.sort function to sort the list in ascending order.
  •  Print the third last element.

Program:

import java.util.*;
public class Main
{
    public static void main(String args[])
    {
        // Creating the array
        Integer arr[] = {12, 2, 34, 20, 54, 6};
        
        // Prints the array elements
        printArray(arr);
        
        // Converts the array into a list
        List<Integer> list=Arrays.asList(arr);

        // Sorts the array in ascending order  
        Collections.sort(list);
        
        // Prints the third largest element
        System.out.println("The third largest element of the array is: "+list.get(arr.length-3));
    }

    // Function to print the array
    static void printArray(Integer arr[])
    {
        System.out.println("The array elements are");
        for(int i = 0; i < arr.length ; i++)
            System.out.print(arr[i]+" ");
        System.out.println();
    }
}

Output:

The array elements are
12 2 34 20 54 6 
The third largest element of the array is: 20

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