#include <stdio.h> 
/* Define display_trade_price first */
void display_trade_price (double p, int n) {
  printf ("The total value of the trade is %f.\n", p * n);
}
/* Then, define main */
main ( ) {
  double price = 10.2;
  int number = 600;
  display_trade_price (price, number);
}