/* Exercise 3.20 Solution */
#include <stdio.h>

main()
{
   float principal, rate, interest;
   int term;
   
   printf("Enter loan principal (-1 to end): ");
   scanf("%f", &principal);

   while (principal != -1.0) {
      printf("Enter interest rate: ");
      scanf("%f", &rate);
      printf("Enter term of the loan in days: ");
      scanf("%d", &term);
      
      interest = principal * rate * term / 365.0;
      printf("The interest charge is $%.2f\n\n", interest);

      printf("Enter loan principal (-1 to end): ");
      scanf("%f", &principal);
   }

   return 0;
}