public member type
<unordered_set>
key_equal key_eq() const;
Get key equivalence predicate
Returns the key equivalence comparison predicate used by the unordered_set container.
The key equivalence comparison is a predicate that takes the value of two elements as arguments and returns a bool value indicating whether they are to be considered equivalent. It is adopted by the container on construction (see unordered_set's constructor for more info). By default, it is equal_to<key_type>, which returns the same as applying the equal-to operator (==) to the arguments.
Return Value
The key equality comparison object.
Member type key_equal is the type of the key equality comparison predicate used by the container, defined in unordered_set as an alias of its third template parameter (Pred).
Example
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// unordered_set::key_eq
#include <iostream>
#include <string>
#include <unordered_set>
int main ()
{
std::unordered_set<std::string> myset;
bool case_insensitive = myset.key_eq()("checking","CHECKING");
std::cout << "myset.key_eq() is ";
std::cout << ( case_insensitive ? "case insensitive" : "case sensitive" );
std::cout << std::endl;
return 0;
}
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Output:
myset.key_eq() is case sensitive
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Iterator validity
No changes.