Does arduino provide such functionality? Variable argument list for functions?
#include <cstdarg>
double average ( int num, ... ){
va_list arguments; // A place to store the list of arguments
double sum = 0;
va_start ( arguments, num ); // Initializing arguments to store all values after num
for ( int x = 0; x < num; x++ ) // Loop until all numbers are added
sum += va_arg ( arguments, double ); // Adds the next value in argument list to sum.
va_end ( arguments ); // Cleans up the list
return sum / num; // Returns some number (typecast prevents truncation)
}