// Chap 5, pp 210 - 211
// Includes WriteForward and WriteBackward2.
#include <iostream.h>
#include <string.h>

typedef struct nodeType* ptrType;
struct nodeType
{  char    Data;
   ptrType Next;
};  // end struct

void WriteForward(ptrType StringPtr)
// ---------------------------------------------------------
// Writes a string.
// Precondition: The string is represented as a linked list
// to which the pointer StringPtr points.
// Postcondition: The string is displayed. The linked list
// and StringPtr are unchanged.
// ---------------------------------------------------------
{
   if (StringPtr != NULL)
   {  // write the first character
      cout << StringPtr->Data;

      // write the string minus its first character
      WriteForward(StringPtr->Next);
   }  // end if
}  // end WriteForward

void WriteBackward2(ptrType StringPtr)
// ---------------------------------------------------------
// Writes a string backward.
// Precondition: The string is represented as a linked list
// to which the pointer StringPtr points.
// Postcondition: The string is displayed backward. The
// linked list and StringPtr are unchanged.
// ---------------------------------------------------------
{
   if (StringPtr != NULL)
   {  // write the string minus its first character backward
      WriteBackward2(StringPtr->Next);

      // write the first character
      cout << StringPtr->Data;
   }  // end if
}  // end WriteBackward2

// ******SAMPLE MAIN PROGRAM******
main()
{  const int StringLength = 80;
   typedef char stringType[StringLength];
   stringType InString;
   ptrType StringPtr, Trav;
   int Counter;

   cout << "Enter a string: ";
   cin >> InString;

   // create a linked list that represents the character string
   StringPtr = new nodeType;
   StringPtr->Data = InString[0];

   Trav = StringPtr;
   for (Counter = 2; Counter <= strlen(InString); ++Counter)
   {  Trav->Next = new nodeType;
      Trav = Trav->Next;
      Trav->Data = InString[Counter-1];
   }  // end for
   Trav->Next = NULL;

   // demonstrate WriteForward and WriteBackward2
   cout << "\n\nThe string written forward is ===> ";
   WriteForward(StringPtr);

   cout << "\n\nThe string written backward is ==> ";
   WriteBackward2(StringPtr);
   cout << "\n\n";

   return 0;
}