map::equal_range

傳回表示金鑰的 lower_bound 和索引鍵的 upper_bound 的一組 Iterator。

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

參數

• _Key
  引數索引鍵值與項目的排序鍵會比較搜尋的對應。

傳回值

若要存取一個至 pr 的第一個 Iterator 的成員函式傳回，則使用 pr。first和取值下限 Iterator，使用* (pr。first)。 若要存取一個至 pr 的第二個 Iterator 之成員函式傳回，則使用 pr。second和取值上限 Iterator，使用* (pr。second)。

範例

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

int main( )
{
   using namespace std; 
   typedef map <int, int, less<int> > IntMap;
   IntMap m1;
   map <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 <IntMap::const_iterator, IntMap::const_iterator> p1, p2;
   p1 = m1.equal_range( 2 );

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

   cout << "The upper bound of the element with "
        << "a key of 2 in the map 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 map m1 doesn't have an element "
           << "with a key less than 40." << endl;
   else
      cout << "The element of map m1 with a key >= 40 is: "
           << p2.first -> first << "." << endl;
}

需求

標頭：<map>

命名空間: std

請參閱

參考

map 類別

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