How to Find the Median of Vector Elements in C++?

Median of a dataset is defined as the middle element when N(size of vector) is odd and the average of the middle two elements when N is even in the sorted dataset. In this article, we will learn how to find the median of all the elements of a vector in C++.

For Example

Input:
myVector = {3, 1, 6, 2, 5}
Output:
Median is: 3

Finding Median of Elements Stored in a Vector

To compute the median of all elements in a std::vector first and sort the vector using std::sort. If the number of elements in a vector is odd then the middle element is the median, otherwise for an even number of elements the average of two middle elements is a median.

C++ Program to Find Median of All Elements in Vector

// C++ Program to calculate the median of a vector of
// integers
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

// Function for calculating median
double Median(vector<int> v, int n)
{
    // Sort the vector
    sort(v.begin(), v.end());

    // Check if the number of elements is odd
    if (n % 2 != 0)
        return (double)v[n / 2];

    // If the number of elements is even, return the average
    // of the two middle elements
    return (double)(v[(n - 1) / 2] + v[n / 2]) / 2.0;
}

int main()
{
    // initializing vector
    vector<int> v = { 5, 7, 4, 2, 6, 2, 8, 3 };
    // finding size of vector
    int N = v.size();
    // print the median
    cout << "Median = " << Median(v, N) << endl;
    return 0;
}

Median = 4.5

Time Complexity: O(N log N), where N is the number of element in a vector.
Auxiliary Space: O(1)