C++ for Dummies (3rd Edition)/C_FD.iso/BUDGETS/BUDGET5_1.CPP

C/C++ Source or Header | 1996-09-15 | 8KB | 318 lines

//BUDGET5.1c - this version splits the linked list into two
//            by establishing two different pFirst pointers,
//            one to the first Checking account object and
//            the other to the first Savings account object.
//
//            This is the solution to problem 1c.
//

#include <iostream.h>
#include <stdlib.h>
#include <ctype.h>
//Account - this abstract class incorporates properties
//          common to both account types Checking and
//          Savings; however, itÆs missing the concept
//          withdrawal( ) which is different between the two
class Account
{
  protected:
   Account(Account &c)
   {
      cout << "No creating funds\n";
   }

   //this function adds an object to the list pointed
   //at by the argument provided to the function
   void addToList(Account * &pFirst);            //Note 1

  public:
   Account(unsigned accNo, float initialBalance = 0.0F);

   //access functions
   int accountNo( )
   {
      return accountNumber;
   }
   float acntBalance( )
   {
      return balance;
   }

   static int noAccounts( )
   {
      return count;
   }

   //transaction functions
   void deposit(float amount)
   {
      balance += amount;
   }
   virtual void withdrawal(float amount) = 0;

   //display function for displaying self on æcoutÆ
   void display( )
   {
      cout << "Account " << accountNumber
           << " = "      << balance
           << "\n";
   }

   //make the following functions pure virtual
   Account *next( )
   {
      return pNext;
   }


  protected:
   static int count;         //number of accounts
   unsigned   accountNumber;
   float      balance;

   //pNext is still in Account but pFirst        //Note 2
   //has now been relegated to the subclasses
   Account   *pNext;
};
int Account::count = 0;

Account::Account(unsigned accNo, float initialBalance)
{
   accountNumber = accNo;
   balance = initialBalance;
   count++;
}

//addToList - by accepting a reference to pFirst
//            as an argument, addToList( ) can be called
//            from either Checking or Savings
void Account::addToList(Account * &pFirst)
{
   //this comes out of the constructor for Account
   Account* pA;
   if (pFirst == 0)
   {
      pFirst = this;      //empty list; make it first
   }
   else {                 //list not empty; look for last...
                          //...entry in the list
      for (pA = pFirst; pA->pNext; pA = pA->pNext)
      {
      }
      pA->pNext = this;   //tack us onto end
   }
   pNext = 0;             //weÆre always last
}

//Checking - this class contains properties unique to
//           checking accounts.  Not much left is there?
class Checking : public Account
{
  public:
   //here the constructor defined inline
   Checking(unsigned accNo, float initialBalance = 0.0F) :
       Account(accNo, initialBalance)
   {
     addToList(Checking::pFirst);                //Note 3
   }

   //overload pure virtual functions
   virtual void withdrawal(float amount);

   //return first object in Checking account list
   static Account* first( )                       //Note 4
   {
      return (Account*)Checking::pFirst;
   }
  protected:
   static Account* pFirst;
};
Account *Checking::pFirst = 0;

void Checking::withdrawal(float amount)
{
   if (balance < amount)
   {
      cout << "Insufficient funds: balance " << balance
           << ", check "                     << amount
           << "\n";
   }
   else
   {
      balance -= amount;

      //if balance falls too low, charge service fee
      if (balance < 500.00F)
      {
         balance -= 0.20F;
      }
   }
}


//Savings - same story as Checking except that it also
//          has a unique data member
class Savings : public Account
{
  public:
   //here the constructor is defined as a separate
   //function just to show you the difference
   Savings(unsigned accNo, float initialBalance = 0.0F) :
      Account(accNo, initialBalance)
   {
      noWithdrawals = 0;
      addToList(Savings::pFirst);
   }

   //transaction functions
   virtual void withdrawal(float amount);
   static Account* first( )
   {
      return (Account*)Savings::pFirst;
   }


  protected:
   int        noWithdrawals;
   static Account *pFirst;
};
Account* Savings::pFirst = 0;

void Savings::withdrawal(float amount)
{
   if (balance < amount)
   {
      cout << "Insufficient funds: balance " << balance
           << ", withdrawal "                << amount
           << "\n";
   }
   else
   {
      if (++noWithdrawals > 1)
      {
         balance -= 5.00F;
      }
      balance -= amount;
   }
}

//prototype declarations
unsigned getAccntNo( );
void process(Account &account);
void outOfMemory( );


//main - accumulate the initial input and output totals
int main( )
{
   /*loop until someone enters an æXÆ or æxÆ*/
   Account *pA;
   char     accountType;     //S or C

   unsigned keepLooping = 1;
   while (keepLooping)
   {
      cout << "Enter S for Savings, "
              "C for Checking, X for exit\n";
      cin  >> accountType;

      switch (accountType)
      {
         case 'c':
         case 'C':
            pA = new Checking(getAccntNo( ));
            if (pA == 0)
            {
               outOfMemory( );
            }
            process(*pA);
            break;

         case 's':
         case 'S':
            pA = new Savings(getAccntNo( ));
            if (pA == 0)
            {
               outOfMemory( );
            }
            process(*pA);
            break;
         case 'x':
         case 'X':
            keepLooping = 0;
            break;

         default:
            cout << "I didn't get that.\n";
      }
   }

   //now present totals                          //Note 5
   float subTotal = 0.0F;
   float total = 0.0F;
   cout << "Account totals:\n";

   //we are now forced to display the lists separately
   for (pA = Checking::first( ); pA; pA = pA->next( ))
   {
      pA->display( );
      subTotal += pA->acntBalance( );
   }
   cout << "Total of all checking accounts = " << subTotal << "\n";
   total += subTotal;

   //repeat the process for savings
   subTotal = 0.0F;
   for (pA = Savings::first( ); pA; pA = pA->next( ))
   {
      pA->display( );
      subTotal += pA->acntBalance( );
   }
   cout << "Total of all savings accounts = " << subTotal << "\n";
   total += subTotal;

   cout << "Total worth of all accounts   = " << total << "\n";
   return 0;
}

//getAccntNo - return the account number entered
unsigned getAccntNo( )
{
   unsigned accntNo;
   cout << "Enter account number:";
   cin  >> accntNo;
   return accntNo;
}

//process(Account) - input the data for an account*/
void process(Account &account)
{
   cout << "Enter positive number for deposit,\n"
           "negative for withdrawal, 0 to terminate";

   float transaction;
   do
   {
      cout << ":";
      cin  >> transaction;

      //deposit
      if (transaction > 0.0F)
      {
         account.deposit(transaction);
      }

      //withdrawal
      if (transaction < 0.0F) {
         account.withdrawal(-transaction);
      }
   } while (transaction != 0.0F);
}

//outOfMemory - generate out-of-memory message and quit
void outOfMemory( )
{
   cout << "Out of memory\n";
   abort( );
}