Java Program to find largest element in an array

Given an array, find the largest element in it.

Input : arr[] = {10, 20, 4}
Output : 20

Input : arr[] = {20, 10, 20, 4, 100}
Output : 100

Method 1: Iterative Way

Java

// Java Program to find maximum in arr[]
class Test
{
    static int arr[] = {10, 324, 45, 90, 9808};

    // Method to find maximum in arr[]
    static int largest()
    {
        int i;

        // Initialize maximum element
        int max = arr[0];

        // Traverse array elements from second and
        // compare every element with current max
        for (i = 1; i < arr.length; i++)
            if (arr[i] > max)
                max = arr[i];

        return max;
    }

    // Driver method
    public static void main(String[] args)
    {
        System.out.println("Largest in given array is " + largest());
        }
}

Output

Largest in given array is 9808

Output:

Largest in given array is 9808

Time Complexity: O(n), where n represents the size of the given array.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Method 2: Java 8 Stream You can simply use the new Java 8 Streams but you have to work with int. 

Java

import java.util.Arrays;

public class GFG {
    public static void main(String[] args){
        int arr[] = {10, 324, 45, 90, 9808};
        int max = Arrays.stream(arr).max().getAsInt();
        System.out.println("Largest in given array is " +max);
    }

}

Output

Largest in given array is 9808

Output:

Largest in given array is 9808

Time Complexity: O(n), where n represents the size of the given array.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Method 3 : (Sorting)

Java

// Java program to find maximum in
// arr[] of size n
import java .io.*;
import java.util.*;

class GFG
{
    // returns maximum in arr[] of size n
    static int largest(int []arr,
                       int n)
    {
        Arrays.sort(arr);
        return arr[n - 1];
    }

    // Driver code
    static public void main (String[] args)
    {
        int []arr = {10, 324, 45,
                     90, 9808};
        int n = arr.length;
        System.out.println(largest(arr, n));
    }
}

Output

9808

Alternate way to write same Program  without using any user defined function :

Java

/*package whatever //do not write package name here */

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

class GFG {
    public static void main (String[] args) {
        int arr[]={12,45,67,89,100,23,3456,897,452,444,899,700};
          Arrays.sort(arr);
          System.out.println("Largest number from given array: "+arr[arr.length-1]);
    }
}

Output

Largest number from given array: 3456

Time Complexity: O(n logn), where n represents the size of the given array.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Please refer complete article on Program to find largest element in an array for more details!

Method 4: Using Collections.max()

Define an empty ArrayList and add all elements of array to it.Pass this ArrayList to Collections.max().The max() method of java.util.Collections class is used to return the maximum element of the given collection, according to the natural ordering of its elements.

Java

import java.util.*;
public class GFG {
    public static void main(String[] args){
        int arr[] = {10, 324, 45, 90, 9808};
        List<Integer> list=new ArrayList<>();
        for(int i=0;i<arr.length;i++)
        {
            list.add(arr[i]);
        }
        System.out.println("Largest in given array is " +Collections.max(list));
    }

}

Output

Largest in given array is 9808