map::rbegin

返回解析的迭代器是相反的映射的第一个元素。

const_reverse_iterator rbegin( ) const; 
reverse_iterator rbegin( );

返回值

解决活动反向双向的迭代器解决在反转的映射的第一个元素或什么是在unreversed映射的最后一个元素。

备注

正 启动 用于映射，rbegin 用于取消的映射。

如果 rbegin 的返回值赋给 const_reverse_iterator，则不能修改映射对象。如果 rbegin 的返回值赋给 reverse_iterator，则可以修改映射对象。

rbegin 可用于通过映射向后重复。

示例

// map_rbegin.cpp
// compile with: /EHsc
#include <map>
#include <iostream>

int main( )
{
   using namespace std;   
   map <int, int> m1;

   map <int, int> :: iterator m1_Iter;
   map <int, int> :: reverse_iterator m1_rIter;
   map <int, int> :: const_reverse_iterator m1_crIter;
   typedef pair <int, int> Int_Pair;

   m1.insert ( Int_Pair ( 1, 10 ) );
   m1.insert ( Int_Pair ( 2, 20 ) );
   m1.insert ( Int_Pair ( 3, 30 ) );

   m1_rIter = m1.rbegin( );
   cout << "The first element of the reversed map m1 is "
        << m1_rIter -> first << "." << endl;

   // begin can be used to start an iteration 
   // through a map in a forward order
   cout << "The map is: ";
   for ( m1_Iter = m1.begin( ) ; m1_Iter != m1.end( ); m1_Iter++)
      cout << m1_Iter -> first << " ";
      cout << "." << endl;

   // rbegin can be used to start an iteration 
   // through a map in a reverse order
   cout << "The reversed map is: ";
   for ( m1_rIter = m1.rbegin( ) ; m1_rIter != m1.rend( ); m1_rIter++)
      cout << m1_rIter -> first << " ";
      cout << "." << endl;

   // A map element can be erased by dereferencing to its key 
   m1_rIter = m1.rbegin( );
   m1.erase ( m1_rIter -> first );

   m1_rIter = m1.rbegin( );
   cout << "After the erasure, the first element "
        << "in the reversed map is "
        << m1_rIter -> first << "." << endl;
}

要求

标头: <map>

命名空间: std

请参见

参考

map Class

标准模板库