hash_multimap::reference

说明
此 API 已过时。另一种方法是 unordered_multimap Class。

提供对元素的类型在 hash_multimap 存储状态。

typedef list<typename _Traits::value_type, typename _Traits::allocator_type>::reference reference;

备注

在 Visual C++ .NET 2003 中，<hash_map> 和 <hash_set> 标头文件的成员中不再标准，命名空间，而是将 stdext 命名空间。有关更多信息，请参见 stdext 命名空间。

示例

// hash_multimap_reference.cpp
// compile with: /EHsc
#include <hash_map>
#include <iostream>

int main( )
{
   using namespace std;
   using namespace stdext;
   hash_multimap <int, int> hm1;
   typedef pair <int, int> Int_Pair;

   hm1.insert ( Int_Pair ( 1, 10 ) );
   hm1.insert ( Int_Pair ( 2, 20 ) );

   // Declare and initialize a const_reference &Ref1 
   // to the key of the first element
   const int &Ref1 = ( hm1.begin( ) -> first );

   // The following line would cause an error as the 
   // non-const_reference cannot be used to access the key
   // int &Ref1 = ( hm1.begin( ) -> first );

   cout << "The key of first element in the hash_multimap is "
        << Ref1 << "." << endl;

   // Declare and initialize a reference &Ref2 
   // to the data value of the first element
   int &Ref2 = ( hm1.begin( ) -> second );

   cout << "The data value of first element in the hash_multimap is "
        << Ref2 << "." << endl;

   //The non-const_reference can be used to modify the 
   //data value of the first element
   Ref2 = Ref2 + 5;
   cout << "The modified data value of first element is "
        << Ref2 << "." << endl;
}

要求

标头： <hash_map>

命名空间： stdext

请参见

参考

hash_multimap Class

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