(Reversing a string with Iterators using Recursion) Write a recursive version of Exercise 18.21.

Question

What will be an ideal response?

Answer 1

```
// Program recursively prints a string backward.
#include
#include
using namespace std;

void printBackward( const string::reverse_iterator,
string::reverse_iterator ); // prototype

int main()
{
string s;

cout << "Enter a string: ";
getline( cin, s );

// reverse_iterator r points
// one location beyond the end of the reverse string
string::reverse_iterator r = s.rend();

// call recursive function printBackward
printBackward( s.rbegin(), r - 1 );
cout << endl;
} // end main

// function to print the reverse string
void printBackward( const string::reverse_iterator s,
string::reverse_iterator rb )
{
// if the end is reached, return
if ( rb == s - 1 )
return;

// recursive call to go through the string
printBackwards( s, rb - 1 );
cout << *rb;
} // end function printBackward
```
Enter a string: print this backward
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