How to find second largest number in an array in Java?

Question

I\'m just practicing some MIT java assignments. But, I\'m not sure how to find the second largest number. http://ocw.csail.mit.edu/f/13

  public class Marath         


        

Answer 1

private static int secLargest(int[] numbers) {
        int maxVal = 0;
        int nextMaxVal = 0;
        for (int i = 0; i < numbers.length; i++) {
            if (numbers[i] > maxVal) {
                nextMaxVal = maxVal;
                maxVal = numbers[i];

            }
            if (numbers[i] < maxVal) {
                nextMaxVal = maxVal;
                maxVal = numbers[i];

            }
        }
        return nextMaxVal;

    }

Answer 2

It will also extract second largest number if largest number occours two times as well as in a single for loop.

import java.util.*;
public class SecondLargestInArray
{
    public static void main(String[] args)
    {
        int arr[] = {99,14,46,47,86,92,52,48,36,66,85,92};
        int largest = arr[0];
        int secondLargest = arr[0];
        System.out.println("The given array is:" );
        for (int i = 0; i < arr.length; i++)
        {
            System.out.print(arr[i]+"\t");
        }

        for (int i = 0; i < arr.length; i++)
        {
            if (arr[i] > largest)
            {
                secondLargest = largest;
                largest = arr[i];
            }
            else if((arr[i]<largest && arr[i]>secondLargest) || largest==secondLargest)
            {
                secondLargest=arr[i];
            }
        }
        System.out.println("\nLargest number is:" + largest);
        System.out.println("\nSecond largest number is:" + secondLargest);
    }
}

Answer 3

    private void secondLargest(int arr[]){

    int maxOne=arr[0];
    int maxTwo=arr[1];

    for(int i=0;i<arr.length;i++){

        if(arr[i]>maxOne){

            maxTwo=maxOne;
            maxOne=arr[i];
        }else if (arr[i]>maxTwo) {

            maxTwo=arr[i];
        }

    }

    System.out.println(maxOne);
    System.out.println(maxTwo);
}

Answer 4

PHP ALGO

if $arr is given array

$a = 0; $b = 0; // These are two variables and set their value to minimum
 $i = 0 ; // this is incremental variable
 loop $i till count($arr)   // loop the array using foreach or for-loop till length of array
    if( $arr[i] > $a || $arr[i] > $b) 
       ($a < $b) ? $a = $arr[i]: $b = $arr[i] ; // this is conditional operator 
    loop ends

    echo 'Second largest number is : '. ($a < $b)? $a : $b;  // this is conditional operator and you can output the smallest of final two number 

*The variable declaration and output is different but you can take the logic from it.