Project Three Solution

/* A boat rental company has three types of boats.
   The type of the boat depends on the number of 
   persons the boat can carry. */

int show_menu ( void );
/* shows the menu of the four possible options */

int select_type ( int n1, int n2, int n3 );
/* prompts the user for a selection of type boats
   and checks the availability */

void prn_available ( int n1, int n2, int n3 );
/* prints the number of available boats */

int available ( int n1, int n2, int n3, int n );
/* returns 1 if type n boat is available, 0 otherwise */

void boat_renting ( int n1, int n2, int n3 );
/* runs a boat renting session with three types of boats */

#include <stdio.h>

int main(void)
{
   int n1,n2,n3,choice,n;

   printf("\nWelcome to our boat rental company! \n");
   printf("  Give number of 1-person boats : ");
   scanf("%d", &n1);
   printf("  Give number of 2-person boats : ");
   scanf("%d", &n2);
   printf("  Give number of 3-person boats : ");
   scanf("%d", &n3);
  
   boat_renting(n1,n2,n3);

   return 0;
}

int show_menu ( void )
{
  int choice;

  printf("\nChoose one of the following: \n");
  printf("  0. terminate the program;\n");
  printf("  1. see the number of available boats of each type;\n");
  printf("  2. rent a boat, of a type that is available;\n");
  printf("  3. return a boat.\n");
  printf("Type 0,1,2, or 3 to select : "); 
  scanf("%d", &choice);

  return choice;
}

int select_type ( int n1, int n2, int n3 )
{
  int choose_type;

  printf("\nFor how many persons ? ");
  scanf("%d", &choose_type);

  if ((choose_type < 0) || (choose_type > 3)
      || (available(n1,n2,n3,choose_type) == 0))
  {
     printf("Sorry, no %d-person boat available.\n", choose_type);
     choose_type = 0;
  }
  else
     printf("Thank you for using our %d-person boat.\n", choose_type);

  return choose_type;
}

void prn_available ( int n1, int n2, int n3 )
{
   printf("\nNumber of 1-person boats available : %d\n", n1);
   printf("Number of 2-person boats available : %d\n", n2);
   printf("Number of 3-person boats available : %d\n", n3);
}

int available ( int n1, int n2, int n3, int n )
{
   switch (n)
   {
      case 1: return (n1 > 0);
      case 2: return (n2 > 0);
      case 3: return (n3 > 0);
   }
}

void boat_renting ( int n1, int n2, int n3 )
{
   int choice,n;

   for (;;)
   {
      choice = show_menu();
      if (choice == 0) break;
      if (choice == 1)
         prn_available(n1,n2,n3);
      else
      {
         n = select_type(n1,n2,n3);
         if (n != 0)
            if (choice == 2)
               switch(n)
               {
                  case 1: n1 = n1 - 1; break;
                  case 2: n2 = n2 - 1; break;
                  case 3: n3 = n3 - 1; break;
               }
            else
               switch(n)
               {
                  case 1: n1 = n1 + 1; break;
                  case 2: n2 = n2 + 1; break;
                  case 3: n3 = n3 + 1; break;
               }
      }
   }
}