multimap::equal_range

找出項目索引鍵符合指定值的元素範圍。

pair <const_iterator, const_iterator> equal_range (
   const Key& _Key
) const;
pair <iterator, iterator> equal_range (
   const Key& _Key
);

參數

• _Key
  引數的索引鍵使用一個項目來排序鍵來比較要搜尋的 multimap 的。

傳回值

一組 Iterator 這樣的第一個是 lower_bound 索引鍵和第二個項目是索引鍵的 upper_bound 。

若要存取一組 pr 的第一個 Iterator 的是如的成員函式傳回的值，使用 pr。first 和取值下限 Iterator，使用* (pr。first)。 若要存取一組 pr 的第二個插入的是如的成員函式傳回的值，使用 pr。second 和取值上限 Iterator，使用* (pr。second)。

範例

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

int main( )
{
   using namespace std;
   typedef multimap <int, int, less<int> > IntMMap;
   IntMMap m1;
   multimap <int, int> :: const_iterator m1_RcIter;
   typedef pair <int, int> Int_Pair;

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

   pair <IntMMap::const_iterator, IntMMap::const_iterator> p1, p2;
   p1 = m1.equal_range( 2 );

   cout << "The lower bound of the element with "
        << "a key of 2 in the multimap m1 is: "
        << p1.first -> second << "." << endl;

   cout << "The upper bound of the element with "
        << "a key of 2 in the multimap m1 is: "
        << p1.second -> second << "." << endl;

   // Compare the upper_bound called directly 
   m1_RcIter = m1.upper_bound( 2 );

   cout << "A direct call of upper_bound( 2 ) gives "
        << m1_RcIter -> second << "," << endl
        << " matching the 2nd element of the pair"
        << " returned by equal_range( 2 )." << endl;

   p2 = m1.equal_range( 4 );

   // If no match is found for the key,
   // both elements of the pair return end( )
   if ( ( p2.first == m1.end( ) ) && ( p2.second == m1.end( ) ) )
      cout << "The multimap m1 doesn't have an element "
           << "with a key less than 4." << endl;
   else
      cout << "The element of multimap m1 with a key >= 40 is: "
           << p1.first -> first << "." << endl;
}

需求

標題: <map>

命名空間: std

請參閱

參考

multimap Class

標準樣板程式庫