From cppreference.com
std::multiset::value_comparevalue_comp()const;Returns the function object that compares the values. It is the same as
.
Return value
The value comparison function object.
Complexity
Constant.
Example
Run this code
#include<iostream>#include<set>#include<utility>// Example module 97 key compare functionstructModCmp{booloperator()(intlhs,intrhs)const{return(lhs%97)<(rhs%97);}};intmain(){std::multiset<int,ModCmp>cont{1,2,3,4,5};// Same behaviour as key_comp()autocomp_func=cont.value_comp();for(constintval{100};constintkey:cont){constboolbefore=comp_func(key,val);constboolafter=comp_func(val,key);std::cout<<"Key ("<<key<<") ";if(!before&&!after)std::cout<<"equivalent to key ("<<val<<")\n";elseif(before)std::cout<<"goes before key ("<<val<<")\n";elseif(after)std::cout<<"goes after key ("<<val<<")\n";elsestd::unreachable();}}Output:
Key (1) goes before key (100) Key (2) goes before key (100) Key (3) equivalent to key (100) Key (4) goes after key (100) Key (5) goes after key (100) See also
returns the function that compares keys
(public member function)