// Pantea Aria 

// void functions
// a function to get two integers and print out their average 

#include <stdio.h>

// function prototype
double average (int number1, int number2);
int main(void) {

    int num1 = 10;
    int num2 = 20;

    // call function average and pass num1 and num2 to it
    // also the function returns a double value, so you must have a place for it too
    double avg = average(num1, num2);
    printf ("The average of num1 and num2 is %lf\n", avg);

    // you can also call a non void function in another function like printf
    printf ("The average of 11 and 12 is %lf\n", average (11, 12));

    return 0;
}
// function definition/body
double average (int number1, int number2) {
    double average_of_numbers = (number1 + number2) / 2.0;

    return average_of_numbers;
    // you can also return it directlyand don't use an extra variable
    // return (number1 + number2) / 2.0;
}