chapter8-18.cpp

C++STL程序员开发指南

//文件名:CHAPTER8-18.cpp
#include <list>
#include <iostream>
#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
#endif
int main( ) 
{
   using namespace std;
   list <int> c1;
   list <int>::iterator c1_Iter;
   list <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
   // list <int>::const_reverse_iterator c1_rIter;
   c1.push_back( 10 );
   c1.push_back( 20 );
   c1.push_back( 30 );
   c1_rIter = c1.rend( );
   c1_rIter --;  // Decrementing a reverse iterator moves it forward in 
                 // the list (to point to the first element here)
   cout << "The first element in the list is: " << *c1_rIter << endl;
   cout << "The list is:";
   for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )
      cout << " " << *c1_Iter;
   cout << endl;
   // rend can be used to test if an iteration is through all of the 
   // elements of a reversed list
   cout << "The reversed list is:";
   for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )
      cout << " " << *c1_rIter;
   cout << endl;
   c1_rIter = c1.rend( );
   c1_rIter--;  // Decrementing the reverse iterator moves it backward 
                // in the reversed list (to the last element here)
   *c1_rIter = 40;  // This modification of the last element would have 
                    // caused an error if a const_reverse iterator had 
                    // been declared (as noted above)
   cout << "The modified reversed list is:";
   for ( c1_rIter = c1.rbegin( ); c1_rIter != c1.rend( ); c1_rIter++ )
      cout << " " << *c1_rIter;
   cout << endl;
   return 0;
}