unordered_set::emplace_hint
Adds an element constructed in place.
template<class ValTy>
iterator emplace_hint(const_iterator where, ValTy&& val);
Parameters
Parameter |
Description |
ValTy |
The in-place constructor argument type. |
val |
Value to insert. |
where |
Where in container to insert (hint only). |
Remarks
The member function returns insert(move(val)).first, using where as a starting place within the controlled sequence to search for the insertion point. (Insertion can possibly occur somewhat faster, if the insertion point immediately precedes or follows where.)
If an exception is thrown during the insertion, the container is left unaltered and the exception is rethrown.
Example
Code
// std_tr1__unordered_set__unordered_set_emplace_hint.cpp
// compile with: /EHsc
#include <unordered_set>
#include <iostream>
#include <string>
unordered_set< string> c1;
string str1("a");
c1.emplace_hint(c1.begin(), move(str1));
cout << "After the emplace insertion, c1 contains: "
<< *c1.begin() << endl;
return (0);
}
Output
After the emplace insertion, c1 contains: a
Requirements
Header: <unordered_set>
Namespace: std