#include <iostream>

using namespace std;

/* FUNCTIONS

returned_type name([arguments])
{
    body_of_the_function
}

*/

// a function which doesn't return any value and doesn't capture any arguments:
void function1()
{
    cout << "The function has been called\n";
}

// a function which doesn't return any value but it takes two arguments
void sum(int a, int b)
{
    cout << a << " + " << b << " = " << a + b << endl;
}

// a function which returns the result (double) and takes two arguments
double divide(int a, int b)
{
    return 1.0 * a / b;
}

int main()
{
    function1();

    sum(17, 18);
    sum(5, 10);
    sum(3, 12);

    int x = 100, y = 20;
    sum(x, y);

    double result = divide(x, y);
    cout << result << endl;
    return 0;
}