Program for harmonic mean of numbers (original) (raw)

Last Updated : 17 Feb, 2023

Given an array of elements, find harmonic mean of numbers.
Examples:

Input : arr[] = {2.0, 1.0} Output : 1.3333 Harmonic mean = 2/(1/2.0 + 1/1.0) = (2 * 2)/3 = 1.333

Input : arr[] = {13.5, 14.5, 14.8, 15.2, 16.1} Output : 14.7707

Harmonic mean is used when average of rates is required, below is the formula.
Harmonic mean of n numbers x1, x2,
x3, . . ., xn can written as below.
Harmonic mean = n / ((1/x1) + (1/x2) + (1/x3) + . . . + (1/xn))

Below is the implementation of Harmonic Mean.

C++ `

// CPP program to find harmonic mean of numbers. #include <bits/stdc++.h> using namespace std;

// Function that returns harmonic mean. float harmonicMean(float arr[], int n) { // Declare sum variables and initialize with zero. float sum = 0; for (int i = 0; i < n; i++) sum = sum + (float)1 / arr[i]; return (float)n / sum; }

// Driver code int main() { float arr[] = { 13.5, 14.5, 14.8, 15.2, 16.1 }; int n = sizeof(arr) / sizeof(arr[0]); cout << harmonicMean(arr, n); return 0; }

// This code is contributed by Aditya Kumar (adityakumar129)

C

// C program to find harmonic mean of numbers. #include <stdio.h>

// Function that returns harmonic mean. float harmonicMean(float arr[], int n) { // Declare sum variables and initialize with zero. float sum = 0; for (int i = 0; i < n; i++) sum = sum + (float)1 / arr[i]; return (float)n / sum; }

// Driver code int main() { float arr[] = { 13.5, 14.5, 14.8, 15.2, 16.1 }; int n = sizeof(arr) / sizeof(arr[0]); printf("%f",harmonicMean(arr, n)); return 0; }

// This code is contributed by Aditya Kumar (adityakumar129)

Java

// JAVA program to find harmonic mean of numbers. import java.io.*;

class GFG {

// Function that returns harmonic mean.
static float harmonicMean(float arr[], int n)
{
    // Declare sum variables and initialize with zero
    float sum = 0;
    for (int i = 0; i < n; i++)
        sum = sum + (float)1 / arr[i];
    return (float)n / sum;
}

// Driver code
public static void main(String args[])
{
    float arr[] = { 13.5f, 14.5f, 14.8f, 15.2f, 16.1f };
    int n = arr.length;
    System.out.println(harmonicMean(arr, n));
}

}

// This code is contributed by Aditya Kumar (adityakumar129)

Python3

Python 3 program to find harmonic

mean of numbers.

Function that returns harmonic mean.

def harmonicMean(arr, n) :

# Declare sum variables and 
# initialize with zero.
sm = 0
for i in range(0, n) :
    sm = sm + (1) / arr[i];

return n / sm

Driver code

arr = [ 13.5, 14.5, 14.8, 15.2, 16.1 ]; n = len(arr) print(harmonicMean(arr, n))

This code is contributed by Nikita Tiwari.

C#

// C# program to find harmonic // mean of numbers. using System;

class GFG {

// Function that returns harmonic mean.
static float harmonicMean(float[] arr, int n)
{
    // Declare sum variables and
    // initialize with zero
    float sum = 0;
    for (int i = 0; i < n; i++)
        sum = sum + (float)1 / arr[i];

    return (float)n / sum;
}

// Driver code
public static void Main()
{
    float[] arr = { 13.5f, 14.5f, 14.8f,
                    15.2f, 16.1f };
    int n = arr.Length;
    Console.WriteLine(harmonicMean(arr, n));
}

}

/This code is contributed by vt_m./

PHP

i<i < i<n; $i++) sum=sum = sum=sum + (float) (1 / arr[arr[arr[i]); return (float)($n / $sum); } // Driver code $arr = array(13.5, 14.5, 14.8, 15.2, 16.1); n=sizeof(n = sizeof(n=sizeof(arr); echo(harmonicMean($arr, $n)); // This code is contributed by Ajit. ?>

JavaScript

`

Output:

14.7707

Time Complexity: O(n)

Auxiliary Space: O(1), since no extra space has been taken.
What if we are given elements and their frequencies?
If we are given n numbers and every number has some frequency then simply we use formula
Harmonic mean = (Frequency-Sum) /((f1/x1) + (f2/x2) + (f3/x3) + . . . + (fn/xn))
Where f1, f2, f3, . . ., fn are the frequencies of elements and x1, 2, x3, . . ., xn are the elements of array.
Frequency-Sum = f1 + f2 + f3, . . ., fn
Examples:

Input : num[] = {13, 14, 15, 16, 17} freq[] = {2, 5, 13, 7, 3} Output : 15.0631

C++ `

// C++ program to find harmonic mean. #include <bits/stdc++.h> using namespace std; // Function that returns harmonic mean. float harmonicMean(int arr[], int freq[], int n) { float sum = 0, frequency_sum = 0; for (int i = 0; i < n; i++) { sum = sum + (float)freq[i] / arr[i]; frequency_sum = frequency_sum + freq[i]; } return frequency_sum / sum; }

// Driver code int main() { int num[] = { 13, 14, 15, 16, 17 }; int freq[] = { 2, 5, 13, 7, 3 }; int n = sizeof(num) / sizeof(num[0]); cout << harmonicMean(num, freq, n); return 0; }

Java

// JAVA program to find harmonic mean.

class GFG {

// Function that returns harmonic mean.
static float harmonicMean(int arr[], int freq[],
                          int n)
{
    float sum = 0, frequency_sum = 0;
    for (int i = 0; i < n; i++) {
        sum = sum + (float)freq[i] / arr[i];
        frequency_sum  = frequency_sum  + freq[i];
    }
    return (frequency_sum / sum);
}
 
// Driver code
public static void main(String args[])
{
    int num[] = { 13, 14, 15, 16, 17 };
    int freq[] = { 2, 5, 13, 7, 3 };
    int n = num.length;
    System.out.println(harmonicMean(num, freq, n));
}

}

/This code is contributed by Nikita Tiwari./

Python3

Python 3 program to find harmonic mean.

Function that returns harmonic mean.

def harmonicMean(arr, freq, n) : sm = 0 frequency_sum = 0 for i in range(0,n) : sm = sm + freq[i] / arr[i] frequency_sum = frequency_sum + freq[i]

return (round(frequency_sum / sm,4))

Driver code

num = [ 13, 14, 15, 16, 17 ] freq = [ 2, 5, 13, 7, 3 ] n = len(num) print (harmonicMean(num, freq, n))

This code is contributed by Nikita Tiwari.

C#

// C# program to find harmonic mean. using System;

class GFG {

// Function that returns harmonic mean.
static float harmonicMean(int[] arr, int[] freq,
                                          int n)
{
    float sum = 0, frequency_sum = 0;
    for (int i = 0; i < n; i++) {
        sum = sum + (float)freq[i] / arr[i];
        frequency_sum = frequency_sum + freq[i];
    }
    return (frequency_sum / sum);
}

// Driver code
public static void Main()
{
    int[] num = { 13, 14, 15, 16, 17 };
    int[] freq = { 2, 5, 13, 7, 3 };
    int n = num.Length;
    Console.WriteLine(harmonicMean(num, freq, n));
}

}

/This code is contributed by vt_m./

PHP

freq,freq, freq,n) { sum=0;sum = 0; sum=0;frequency_sum = 0; for ($i = 0; i<i < i<n; $i++) { sum=sum = sum=sum + (float) ($freq[$i] / arr[arr[arr[i]); frequencysum=frequency_sum = frequencys​um=frequency_sum + freq[freq[freq[i]; } return ($frequency_sum / $sum); } // Driver code $num = array(13, 14, 15, 16, 17); $freq = array(2, 5, 13, 7, 3); n=sizeof(n = sizeof(n=sizeof(num); echo(harmonicMean($num, freq,freq, freq,n)); // This code is contributed by Ajit. ?>

JavaScript

`

Output:

15.0631

Time Complexity: O(n)

Auxiliary Space: O(1)
Harmonic mean of numbers using harmonic_mean() in Python:
Simple Python program to find harmonic mean using harmonic_mean() function.

Python3 `

#'harmonic_mean()' new function added in 'Python3.6' onwards. #Program calculates Harmonic Mean using harmonic_mean()

#imports Python statistics library import statistics def harmonic_mean(): list= [13.5, 14.5, 14.8, 15.2, 16.1] print(statistics.harmonic_mean(list))

#Driver code harmonic_mean()

#This code is contributed by 'Abhishek Agrawal'.

`

Output: 14.770680729373778

Time Complexity: O(n)

Auxiliary Space: O(1)