/** 
 * @brief classify 5 cards according to poker
 *        rules
 *
 * Determines whether the hand contains a
 * straight, a flush, four-of-a-kind, and/or
 * three-of-a-kind; determines the number of
 * pairs.
 * 
 * @side_effect stores the classification into
 *   external variables.
 */
void analyze_hand(void){
};