getting second largest element of the array

 Naive approach

#include <iostream>

// naive solution 2 times traversal of the array;

int getlargest(int arr[], int size)

{

    // focus is to get largest elements index

    int largest = 0;

    for (int i = 0; i < size; i++)

    {

        if (arr[i] > arr[largest])

        {

            largest = i;

        }

    }

    return largest;

}

int secondlargest(int vec[], int n)

{

    int lar = getlargest(vec, n);

    int selar = -1;

    for (int i = 0; i < n; i++)

    {

        if (vec[i] != vec[lar])

        {

            if (selar == i)

                selar = i;

            else if (vec[i] < vec[lar])

                selar = i;

        }

    }

    return selar;

}

int main()

{

    int arraa[] = {1, 3, 2, 0};

    int sizes = sizeof(arraa) / sizeof(arraa[0]);

    std::cout << sizes << std::endl;

    std::cout << "The largest element of the array is: " << getlargest(arraa, sizes) << std::endl;

    std::cout << "The second largest element of the array is: " << secondlargest(arraa, sizes) << std::endl;

}

efficient approach

#include <iostream>

int getSlargest(int arr[], int size)

{

    int largest = 0, seclar = -1;

    for (int i = 0; i < size; i++)

    {

        if (arr[i] > arr[largest])

        {

            seclar = largest;

            largest = i;

        }

        else if (arr[i] != arr[largest])

        {

            if (seclar == -1 || arr[i] > arr[seclar])

                seclar = i;

        }

    }

    return seclar;

}

int main()

{

    std::cout << "appropriate approach to find the second largest element of the array" << std::endl;

    int arr[] = {1, 132, 12, 10};

    int sizeofarr = sizeof(arr) / sizeof(arr[0]);

    std::cout << "size of array = " << sizeofarr << std::endl;

    std::cout << getSlargest(arr, sizeofarr) << std::endl;

    std::cin.get();

}