set::rbegin and set::rend (STL Sample)

The sample code below illustrates how to use the set::rbegin and set::rend STL functions in Visual C++.

Required Header:
<set>

template<class _K, class _Pr, class _A>
     class set 
     {
         public:
         // Function 1:
         const_reverse_iterator rbegin() const;
         // Function 2:
         const_reverse_iterator rend() const;
     }

Note: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

Description:
The rbegin function returns a reverse bidirectional iterator that points just beyond the end of the controlled sequence. The rend function returns a reverse bidirectional iterator that points at the first element of the sequence.

Sample Code:

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: -GX
//
// SetRbeginRend.cpp:
//      Illustrates how to use the rbegin function to get a reverse
//      bidirectional iterator that points just beyond the end of
//      the controlled sequence. It also illustrates how to use
//      the rend function to get a reverse bidirectional iterator
//      that points at the first element of the sequence.
//
// Functions:
//
//    rbegin      Returns a reverse bidirectional iterator that points
//                just beyond the end of the controlled sequence.
//    rend        Returns a reverse bidirectional iterator that points
//                at the first element of the sequence.
//
//////////////////////////////////////////////////////////////////////

#pragma warning(disable:4786)
#include <set>
#include <iostream>

using namespace std ;

typedef set<int> SET_INT;

void main() {
  SET_INT s1;
  SET_INT::reverse_iterator i;
  cout << "s1.insert(5)" << endl;
  s1.insert(5);
  cout << "s1.insert(10)" << endl;
  s1.insert(10);
  cout << "s1.insert(15)" << endl;
  s1.insert(15);
  cout << "s1.insert(20)" << endl;
  s1.insert(20);

  // displays: 20,15,10,5
  for (i=s1.rbegin();i!=s1.rend();i++)
     cout << "s1 has " << *i << " in its set." << endl;
}

 

Program Output is:

s1.insert(5)
s1.insert(10)
s1.insert(15)
s1.insert(20)
s1 has 20 in its set.
s1 has 15 in its set.
s1 has 10 in its set.
s1 has 5 in its set.