hash_multimap::value_type

表示对象类型的类型。hash_multimap 存储。

typedef pair<const Key, Type> value_type;

备注

使用非常数迭代器，或引用，因为一关联容器中的密钥不能更改value_type 声明为 pair*<const key_typemapped_type>pair<，而不是key_type，mapped_type>。*

在Visual C++ .NET 2003中，成员<hash_map> 和 <hash_set> 头文件不再在std命名空间，而是已经进入了stdext命名空间。 有关更多信息，请参见 stdext 命名空间。

示例

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

int main( )
{
   using namespace std;
   using namespace stdext;
   typedef pair <const int, int> cInt2Int;
   hash_multimap <int, int> hm1;
   hash_multimap <int, int> :: key_type key1;
   hash_multimap <int, int> :: mapped_type mapped1;
   hash_multimap <int, int> :: value_type value1;
   hash_multimap <int, int> :: iterator pIter;
   
   // value_type can be used to pass the correct type
   // explicitely to avoid implicit type conversion
   hm1.insert ( hash_multimap <int, int> :: value_type ( 1, 10 ) );

   // Compare another way to insert objects into a hash_multimap
   hm1.insert ( cInt2Int ( 2, 20 ) );

   // Initializing key1 and mapped1
   key1 = ( hm1.begin( ) -> first );
   mapped1 = ( hm1.begin( ) -> second );

   cout << "The key of first element in the hash_multimap is "
        << key1 << "." << endl;

   cout << "The data value of first element in the hash_multimap is "
        << mapped1 << "." << endl;

   // The following line would cause an error because
   // the value_type is not assignable
   // value1 = cInt2Int ( 4, 40 );

   cout  << "The keys of the mapped elements are:";
   for ( pIter = hm1.begin( ) ; pIter != hm1.end( ) ; pIter++ )
      cout << " " << pIter -> first;
   cout << "." << endl;

   cout  << "The values of the mapped elements are:";
   for ( pIter = hm1.begin( ) ; pIter != hm1.end( ) ; pIter++ )
      cout << " " << pIter -> second;
   cout << "." << endl;
}

要求

标头: <hash_map>

**命名空间：**stdext

请参见

参考

hash_multimap 类

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