649: Mainline

Suppose, for the sake of illustration, that you have a version of analyze_trades that uses two subfunctions, mean_price and mean_size:

double mean_price (struct trade **array, int length) { 
  int counter; double sum = 0.0;  
  for (counter = 0; counter < length; ++counter) 
    sum = sum + array[counter] -> price; 
  return sum / counter; 
} 
double mean_size (struct trade **array, int length) { 
  int counter; double sum = 0.0;  
  for (counter = 0; counter < length; ++counter) 
    sum = sum + array[counter] -> number; 
  return sum / counter; 
}