deque::rbegin
Returns an iterator to the first element in a reversed deque.
const_reverse_iterator rbegin( ) const;
reverse_iterator rbegin( );
Return Value
A reverse random-access iterator addressing the first element in a reversed deque or addressing what had been the last element in the unreversed deque.
Remarks
rbegin is used with a reversed deque just as begin is used with a deque.
If the return value of rbegin is assigned to a const_reverse_iterator, the deque object cannot be modified. If the return value of rbegin is assigned to a reverse_iterator, the deque object can be modified.
rbegin can be used to iterate through a deque backwards.
Example
// deque_rbegin.cpp
// compile with: /EHsc
#include <deque>
#include <iostream>
int main( )
{
using namespace std;
deque <int> c1;
deque <int>::iterator c1_Iter;
deque <int>::reverse_iterator c1_rIter;
// If the following line had replaced the line above, an error
// would have resulted in the line modifying an element
// (commented below) because the iterator would have been const
// deque <int>::const_reverse_iterator c1_rIter;
c1.push_back( 10 );
c1.push_back( 20 );
c1.push_back( 30 );
c1_rIter = c1.rbegin( );
cout << "Last element in the deque is " << *c1_rIter << "." << endl;
cout << "The deque contains the elements: ";
for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )
cout << *c1_Iter << " ";
cout << "in that order.";
cout << endl;
// rbegin can be used to iterate through a deque in reverse order
cout << "The reversed deque is: ";
for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )
cout << *c1_rIter << " ";
cout << endl;
c1_rIter = c1.rbegin( );
*c1_rIter = 40; // This would have caused an error if a
// const_reverse iterator had been declared as
// noted above
cout << "Last element in deque is now " << *c1_rIter << "." << endl;
}
Output
Last element in the deque is 30. The deque contains the elements: 10 20 30 in that order. The reversed deque is: 30 20 10 Last element in deque is now 40.
Requirements
Header: <deque>
Namespace: std