multimap::equal_range

查找元素键与指定值元素的范围。

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

参数

• _Key
  参数键与一个元素的排序关键字进行比较从要搜索的基于的。

返回值

迭代器对这样的第一个是 lower_bound 键和第二是键的 upper_bound。

为对第一个迭代 pr 跟成员函数返回的访问，请使用 pr。first 和取消引用下限迭代器，使用* (pr。first)。为对第二个迭代 pr 跟成员函数返回的访问，请使用 pr。second 和取消引用上限迭代器，使用* (pr。second)。

示例

// 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;
}

要求

标头: <map>

命名空间: std

请参见

参考

multimap Class

标准模板库