C Program to Find Second Largest Number in an Array

The program finds the second largest element persistent in the given an array of integers.

For Example:
Sample Input: arr[] = {8, 1, 18, 9, 13, 5}
Sample Output: The second largest element is 13.
Explanation: The largest element of the array is 18 and the second largest element is 13

/* C Program to find Second largest Number in an Array */

#include <stdio.h>
#include <limits.h>

int main()
{
    int arr[50], i, size, firstL, secondL;

    printf("Please Enter the Number of elements in an array : \n");
    scanf("%d", &size);

    printf("Please Enter %d elements of an Array \n", size);
    for (i = 0; i < size; i++)
    {
        scanf("%d", &arr[i]);
    }

    firstL = secondL = INT_MIN;

    for (i = 0; i < size; i++)
    {
        if(arr[i] > firstL)
        {
            secondL = firstL;
            firstL = arr[i];
        }
        else if(arr[i] > secondL && arr[i] < firstL)
        {
            secondL = arr[i];
        }
    }

    printf("\nThe Largest Number in this Array = %d", firstL);
    if (secondL == INT_MIN)
    {
        printf("The Second Largest Number does not exist.\n");
    }

    else
    {
        printf("\nThe Second Largest Number in this Array = %d", secondL);
    }

    return 0;
}

 

 

Test Case 1:
Please Enter the Number of elements in an array :
5
Please Enter 5 elements of an Array
10
14
25
4
8

The Largest Number in this Array = 25
The Second Largest Number in this Array = 14

Test Case 2:
Please Enter the Number of elements in an array :
3
Please Enter 3 elements of an Array
14
14
8

The Largest Number in this Array = 14
The Second Largest Number in this Array = 8

 

Test Case 3:
Please Enter the Number of elements in an array :
3
Please Enter 3 elements of an Array
5
3
3

The Largest Number in this Array = 5
The Second Largest Number in this Array = 3

Test Case 4:
Please Enter the Number of elements in an array :
4
Please Enter 4 elements of an Array
8
8
8
8

The Largest Number in this Array = 8
The Second Largest Number does not exist.