C / C++ / MFC

Maximilien wrote:

no need to keep an history of the input, just "accumulate"...

double sum_array( int size, double values[] )
{
	if( size > 0 ) return values[0] + sum_array( size - 1, values + 1 );
	return 0;
}

double average( int size, double values[] )
{
	return sum_array( size, values ) / size;
}

int main()
{
	double values[ 10 ] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 };
	std::cout << average( 10, values ) << std::endl;
}

Aescleal wrote:

Accademic computer scientists love recursion.

double sum(std::size_t size, double values[]) {
   if (0==size)
      return 0.0;
   else
      return sum(size/2, values) + sum(size-size/2, values+size/2);
}
double average(std::size_t size, double values[]) {
   return sum(size, values)/size;
}

double incremental_average(double pre_avg, std::size_t new_size, double new_value) {
   if (new_size > 1)
      return (new_value + pre_avg*(new_size-1))/new_size;
   else
      return new_value;
}
int main () {
   double values[] = {3.5, 5, 7, -2, 3.14, 2.71, 6, 7, 8, 9};
   double avg = 0;
   for (std::size_t i = 0; i < sizeof(values)/sizeof(double); ++i) {
      avg = incremental_average(avg, i+1, values[i]);
      std::cout << "average[" << i+1 << "] = " << avg << std::endl;
   }
}

Flying_Dutchman wrote:

What constitutes a good programmer?