multimap::rbegin
返回解决在已撤消的 multimap 迭代器的第一个元素。
const_reverse_iterator rbegin( ) const;
reverse_iterator rbegin( );
返回值
介绍在其反转的 multimap 的第一个元素或满足针对一双向反向迭代器位于 unreversed multimap 的最后一个元素。
备注
开始 正使用 multimap,rbegin 使用的反转 multimap。
如果返回值 rbegin 为 const_reverse_iterator,则不能修改 multimap 对象。 如果返回值 rbegin 为 reverse_iterator,则可以修改 multimap 对象。
rbegin 可用于通过 multimap 向后循环访问。
示例
// multimap_rbegin.cpp
// compile with: /EHsc
#include <map>
#include <iostream>
int main( )
{
using namespace std;
multimap <int, int> m1;
multimap <int, int> :: iterator m1_Iter;
multimap <int, int> :: reverse_iterator m1_rIter;
multimap <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 multimap m1 is "
<< m1_rIter -> first << "." << endl;
// begin can be used to start an iteration
// throught a multimap in a forward order
cout << "The multimap 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
// throught a multimap in a reverse order
cout << "The reversed multimap is: ";
for ( m1_rIter = m1.rbegin( ) ; m1_rIter != m1.rend( ); m1_rIter++)
cout << m1_rIter -> first << " ";
cout << "." << endl;
// A multimap element can be erased by dereferencing 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 multimap is "
<< m1_rIter -> first << "." << endl;
}
要求
标头: <map>
命名空间: std