(Recursively Print a List Backward) Write a member function printListBackward that re- cursively outputs the items in a linked list object in reverse order. Write a test program that creates a sorted list of integers and prints the list in reverse order.

Question

What will be an ideal response?

Answer 1

```
// List2 class template definition.
#ifndef LIST2_H
#define LIST2_H

#include
using namespace std;

#include "ListNode.h"
#include "List.h"

template< typename NODETYPE >
class List2 : public List< NODETYPE >
{
public:
void recursivePrintReverse() const;
private:
void recursivePrintReverseHelper( ListNode< NODETYPE > * ) const;
}; // end class template List2

// print a list backward recursively.
template< typename NODETYPE >
void List2< NODETYPE >::recursivePrintReverse() const
{
cout << "The list printed recursively backward is:\n";
recursivePrintReverseHelper( firstPtr );
cout << '\n';
} // end function recursivePrintReverse

// helper for printing a list backward recursively.
template< typename NODETYPE >
void List2< NODETYPE >::recursivePrintReverseHelper(
ListNode< NODETYPE > *currentPtr ) const
{
if ( currentPtr == 0 )
return;

recursivePrintReverseHelper( currentPtr->getNextPtr() );
cout << currentPtr->getData() << ' ';
} // end function recursivePrintReverseHelper

#endif
```
```
#include "List2.h"

int main()
{
List2< int > intList;

// insert into list
for ( int i = 1; i <= 10; i++ )
intList.insertAtBack( i );

intList.print();
intList.recursivePrintReverse();
return 0; // indicates successful termination
} // end main
```
The list is: 1 2 3 4 5 6 7 8 9 10
The list printed recursively backward is:
10 9 8 7 6 5 4 3 2 1
Destroying nodes ...
1 2 3 4 5 6 7 8 9 10
All nodes destroyed