Average

Given an array of integers, we want to implement a method to calculate the average of all the numbers in the array. The average of a set of numbers is the sum of those numbers divided by the count of numbers in the set.

Solution

Java

In Java, we can use a for loop to calculate the sum of the elements in the array and then divide it by the length of the array.

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public class AverageCalculator {
    public static double average(int[] numbers) {
        int sum = 0;
        for (int number : numbers) {
            sum += number;
        }
        return (double) sum / numbers.length;
    }

    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40};
        System.out.println("Average: " + average(numbers)); // Output: Average: 25.0
    }
}

C++

In C++, we can use the STL function std::accumulate to calculate the sum, and then divide by the number of elements to calculate the average.

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#include <iostream>
#include <numeric>
#include <vector>

double average(const std::vector<int>& numbers) {
    int sum = std::accumulate(numbers.begin(), numbers.end(), 0);
    return static_cast<double>(sum) / numbers.size();
}

int main() {
    std::vector<int> numbers = {10, 20, 30, 40};
    std::cout << "Average: " << average(numbers) << std::endl; // Output: Average: 25
    return 0;
}

Python

In Python, we can use the built-in sum function to calculate the sum and then divide by the length of the list to find the average.

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def average(numbers):
    return sum(numbers) / len(numbers)

numbers = [10, 20, 30, 40]
print("Average:", average(numbers)) # Output: Average: 25.0

In each language, we’re following the same fundamental approach: calculating the sum of the numbers and dividing by the count to get the average. The differences in implementation are mostly due to language-specific features and idioms.

Without Using Builtin Functions

Below are revised solutions for calculating the average of an array of integers without using any built-in functions.

Java:

In Java, we can iterate through the array using a for loop to calculate the sum and then divide by the length of the array.

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public class AverageCalculator {
    public static double average(int[] numbers) {
        int sum = 0;
        for (int number : numbers) {
            sum += number;
        }
        return (double) sum / numbers.length;
    }

    public static void main(String[] args) {
        int[] numbers = {10, 20, 30, 40};
        System.out.println("Average: " + average(numbers)); // Output: Average: 25.0
    }
}

C++

In C++, we can use a loop to iterate through the elements in the vector and add them together, then divide by the size of the vector to find the average.

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#include <iostream>
#include <vector>

double average(const std::vector<int>& numbers) {
    int sum = 0;
    for (int number : numbers) {
        sum += number;
    }
    return static_cast<double>(sum) / numbers.size();
}

int main() {
    std::vector<int> numbers = {10, 20, 30, 40};
    std::cout << "Average: " << average(numbers) << std::endl; // Output: Average: 25
    return 0;
}

Python

In Python, we can use a for loop to iterate through the list and add the numbers together. Then we can divide the sum by the length of the list.

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def average(numbers):
    sum = 0
    for number in numbers:
        sum += number
    return sum / len(numbers)

numbers = [10, 20, 30, 40]
print("Average:", average(numbers)) # Output: Average: 25.0

Each of these solutions manually calculates the sum of the elements and then divides by the number of elements in the collection. They provide a clear, simple approach to calculating the average without relying on any language-specific built-in functions.

Coding Skill Exercise #13

Average

Implement a method to find the average of all the numbers in an array.

Knowledge Gap Finder

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