unordered_set::equal_range
Finds range that matches a specified key.
std::pair<iterator, iterator>
equal_range(const Key& keyval);
std::pair<const_iterator, const_iterator>
equal_range(const Key& keyval) const;
Parameters
- keyval
Key value to search for.
Remarks
The member function returns a pair of iterators X such that [X.first, X.second) delimits just those elements of the controlled sequence that have equivalent ordering with keyval. If no such elements exist, both iterators are end().
Example
// std_tr1__unordered_set__unordered_set_equal_range.cpp
// compile with: /EHsc
#include <unordered_set>
#include <iostream>
typedef std::unordered_set<char> Myset;
int main()
{
Myset c1;
c1.insert('a');
c1.insert('b');
c1.insert('c');
// display contents " [c] [b] [a]"
for (Myset::const_iterator it = c1.begin();
it != c1.end(); ++it)
std::cout << " [" << *it << "]";
std::cout << std::endl;
// display results of failed search
std::pair<Myset::iterator, Myset::iterator> pair1 =
c1.equal_range('x');
std::cout << "equal_range('x'):";
for (; pair1.first != pair1.second; ++pair1.first)
std::cout << " [" << *pair1.first << "]";
std::cout << std::endl;
// display results of successful search
pair1 = c1.equal_range('b');
std::cout << "equal_range('b'):";
for (; pair1.first != pair1.second; ++pair1.first)
std::cout << " [" << *pair1.first << "]";
std::cout << std::endl;
return (0);
}
[c] [b] [a]
equal_range('x'):
equal_range('b'): [b]
Requirements
Header: <unordered_set>
Namespace: std