What are the fundamental characteristics, data types, and function syntax in programming, and how do you write a C++ program to find the maximum of three variables using a function?

return_type function_name(parameter_type parameter1, parameter_type parameter2, ...) {
    // Function body: statements to be executed
    // return value; // Optional, if return_type is not void
}

int add(int a, int b) {
    return a + b;
}

#include <iostream>
#include <algorithm> // Required for std::max with initializer list

// Function to find the maximum of three integers
int findMax(int num1, int num2, int num3) {
    return std::max({num1, num2, num3});
}

int main() {
    int a, b, c;
    std::cout << "Enter three numbers: ";
    std::cin >> a >> b >> c;
    int maximum = findMax(a, b, c);
    std::cout << "The maximum number is: " << maximum << std::endl;
    return 0;
}

#include <iostream>

int main() {
    int numbers[3]; // Declare an array of 3 integers
    int sum = 0;

    std::cout << "Enter 3 integer elements for the array:" << std::endl;
    for (int i = 0; i < 3; ++i) {
        std::cout << "Element " << i + 1 << ": ";
        std::cin >> numbers[i];
        sum += numbers[i]; // Add current element to sum
    }

    double average = static_cast<double>(sum) / 3.0; // Calculate average

    std::cout << "The elements of the array are: " << numbers[0] << ", " << numbers[1] << ", " << numbers[2] << std::endl;
    std::cout << "The sum of the elements is: " << sum << std::endl;
    std::cout << "The average of the elements is: " << average << std::endl;

    return 0;
}

#include <iostream>

int main() {
    int numbers[3]; // Declare an array of 3 integers
    int sum = 0;

    std::cout << "Enter 3 integer elements for the array:" << std::endl;
    for (int i = 0; i < 3; ++i) {
        std::cout << "Element " << i + 1 << ": ";
        std::cin >> numbers[i];
        sum += numbers[i]; // Add current element to sum
    }

    double average = static_cast<double>(sum) / 3.0; // Calculate average

    std::cout << "The elements of the array are: " << numbers[0] << ", " << numbers[1] << ", " << numbers[2] << std::endl;
    std::cout << "The sum of the elements is: " << sum << std::endl;
    std::cout << "The average of the elements is: " << average << std::endl;

    return 0;
}