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std::multiset::key_comp(3) | C++ Standard Libary | std::multiset::key_comp(3) |
NAME¶
std::multiset::key_comp - std::multiset::key_comp
Synopsis¶
key_compare key_comp() const;
Returns the function object that compares the keys, which is a copy of this
container's constructor argument comp. It is the same as value_comp.
Parameters¶
(none)
Return value¶
The key comparison function object.
Complexity¶
Constant.
Example¶
// Run this code
#include <cassert>
#include <iostream>
#include <set>
// Example module 97 key compare function
struct ModCmp {
bool operator()(const int lhs, const int rhs) const
{
return (lhs % 97) < (rhs % 97);
}
};
int main()
{
std::multiset<int, ModCmp> cont{1, 2, 3, 4, 5};
auto comp_func = cont.key_comp();
for (int key : cont) {
bool before = comp_func(key, 100);
bool after = comp_func(100, key);
if (!before && !after)
std::cout << key << " equivalent to key 100\n";
else if (before)
std::cout << key << " goes before key 100\n";
else if (after)
std::cout << key << " goes after key 100\n";
else
assert(0); // Cannot happen
}
}
Output:¶
1 goes before key 100
2 goes before key 100
3 equivalent to key 100
4 goes after key 100
5 goes after key 100
See also¶
value_comp returns the function that compares keys in objects of
type value_type
(public member function)
2022.07.31 | http://cppreference.com |