SOURCE FILE: changer0.cpp

#include <iostream>
using namespace std ;

int getAmt() ;
bool amtOK (int amount ) ;
void tellAnswer(int amount) ;
void printErrMsg (int amount) ;
int next (int amountLeft) ;
bool wantsToContinue () ;

int main ()
{
  do
  {
    int amount = getAmt() ;
    if   ( amtOK( amount ) )
         tellAnswer( amount ) ;
    else printErrMsg ( amount ) ;
  } while ( wantsToContinue() ) ;
  cout << endl ;
  return 0;
}

  /* Prompt for and retun an amount of cents between 1 and 99 */
int getAmt() 
{
   int amnt ;
   cout << "\nPlease input an amount between 1 and 99 cents: " ;
   cin >> amnt ;
   return amnt ;
}

  /* Return true if and only if 1 <= amount <= 99 */
bool amtOK (int amount)
{
   return ( (amount > 0) && (amount < 100) ) ;
}

  /* Show how to give this amount of money using the fewest coins,
     given that 25, 10, 5, and 1 are the coin denominations 
     available.  */
void tellAnswer(int amount)
{
  int amtLeft = amount ;
  int quarters = 0, dimes = 0, nickels = 0, pennies = 0;
  int nextCoin ;
  while (amtLeft > 0)
  {
    nextCoin = next(amtLeft) ;
    amtLeft = amtLeft - nextCoin ;
    if (nextCoin == 25) quarters++ ;
    else if (nextCoin == 10) dimes++  ;
    else if (nextCoin == 5) nickels++ ;
    else pennies++ ;
  }
  cout << "quarters: " << quarters << endl ;
  cout << "dimes: " << dimes << endl ;
  cout << "nickels: " << nickels << endl ;
  cout << "pennies: " << pennies << endl << endl ;
}

   /* Print the message "Bad Input: Try again." on a line by itself. */
void printErrMsg (int amount)
{
  cout << "Bad Input: Try again.\n\n" ;
}

      /* figure out which coin to give next if the amount left is 
         amountLeft.  Return the value of the coin */
int next (int amountLeft)
{
   int coin ;
   if (amountLeft >= 25)  coin = 25 ;
   else if (amountLeft >= 10) coin = 10 ;
   else if (amountLeft >= 5) coin = 5 ;
   else coin = 1;
   return coin ;
}

   /* Return true if the user wants to solve another problem, 
      else return fals. */
bool wantsToContinue ()
{
  char answer ;
  cout << "Would you like to make change again? (y/n) " ;
  cin >> answer ;  
  return (answer == 'y') ;
}