multiset::multiset
Constructs a multiset that is empty or that is a copy of all or part of some other multiset.
multiset( );
explicit multiset (
const Compare& Comp
);
multiset (
const Compare& Comp,
const Allocator& Al
);
multiset(
const multiset& Right
);
multiset(
multiset&& Right
);
multiset(
initializer_list<Type> IList
);
multiset(
initializer_list<Type> IList,
const Compare& Comp
);
multiset(
initializer_list<Type> IList,
const Compare& Comp,
const Allocator& Al
);
template<class InputIterator>
multiset (
InputIterator First,
InputIterator Last
);
template<class InputIterator>
multiset (
InputIterator First,
InputIterator Last,
const Compare& Comp
);
template<class InputIterator>
multiset (
InputIterator First,
InputIterator Last,
const Compare& Comp,
const Allocator& Al
);
Parameters
Parameter |
Description |
Al |
The storage allocator class to be used for this multiset object, which defaults to Allocator. |
Comp |
The comparison function of type const Compare used to order the elements in the multiset, which defaults to Compare. |
Right |
The multiset of which the constructed multiset is to be a copy. |
First |
The position of the first element in the range of elements to be copied. |
Last |
The position of the first element beyond the range of elements to be copied. |
IList |
The initializer_list from which to copy the elements. |
Remarks
All constructors store a type of allocator object that manages memory storage for the multiset and that can later be returned by calling get_allocator. The allocator parameter is often omitted in the class declarations and preprocessing macros used to substitute alternative allocators.
All constructors initialize their multiset.
All constructors store a function object of type Compare that is used to establish an order among the keys of the multiset and that can later be returned by calling key_comp.
The first three constructors specify an empty initial multiset, the second specifying the type of comparison function (Comp) to be used in establishing the order of the elements and the third explicitly specifying the allocator type (Al) to be used. The keyword explicit suppresses certain kinds of automatic type conversion.
The fourth constructor specifies a copy of the multiset Right.
The fifth constructor specifies a copy of the multiset by moving Right.
The sixth, seventh, and eighth constructors specify an initializer_list from which to copy the elements.
The next three constructors copy the range [First, Last) of a multiset with increasing explicitness in specifying the type of comparison function and allocator.
Example
// multiset_ctor.cpp
// compile with: /EHsc
#include <set>
#include <iostream>
int main()
{
using namespace std;
//multiset <int>::iterator ms1_Iter, ms2_Iter, ms3_Iter;
multiset <int>::iterator ms4_Iter, ms5_Iter, ms6_Iter, ms7_Iter;
// Create an empty multiset ms0 of key type integer
multiset <int> ms0;
// Create an empty multiset ms1 with the key comparison
// function of less than, then insert 4 elements
multiset <int, less<int> > ms1;
ms1.insert(10);
ms1.insert(20);
ms1.insert(20);
ms1.insert(40);
// Create an empty multiset ms2 with the key comparison
// function of geater than, then insert 2 elements
multiset <int, less<int> > ms2;
ms2.insert(10);
ms2.insert(20);
// Create a multiset ms3 with the
// allocator of multiset ms1
multiset <int>::allocator_type ms1_Alloc;
ms1_Alloc = ms1.get_allocator();
multiset <int> ms3(less<int>(), ms1_Alloc);
ms3.insert(30);
// Create a copy, multiset ms4, of multiset ms1
multiset <int> ms4(ms1);
// Create a multiset ms5 by copying the range ms1[_First, _Last)
multiset <int>::const_iterator ms1_bcIter, ms1_ecIter;
ms1_bcIter = ms1.begin();
ms1_ecIter = ms1.begin();
ms1_ecIter++;
ms1_ecIter++;
multiset <int> ms5(ms1_bcIter, ms1_ecIter);
// Create a multiset ms6 by copying the range ms4[_First, _Last)
// and with the allocator of multiset ms2
multiset <int>::allocator_type ms2_Alloc;
ms2_Alloc = ms2.get_allocator();
multiset <int> ms6(ms4.begin(), ++ms4.begin(), less<int>(), ms2_Alloc);
cout << "ms1 =";
for (auto i : ms1)
cout << " " << i;
cout << endl;
cout << "ms2 =";
for (auto i : ms2)
cout << " " << i;
cout << endl;
cout << "ms3 =";
for (auto i : ms3)
cout << " " << i;
cout << endl;
cout << "ms4 =";
for (auto i : ms4)
cout << " " << i;
cout << endl;
cout << "ms5 =";
for (auto i : ms5)
cout << " " << i;
cout << endl;
cout << "ms6 =";
for (auto i : ms6)
cout << " " << i;
cout << endl;
// Create a multiset by moving ms5
multiset<int> ms7(move(ms5));
cout << "ms7 =";
for (auto i : ms7)
cout << " " << i;
cout << endl;
// Create a multiset with an initializer_list
multiset<int> ms8({1, 2, 3, 4});
cout << "ms8=";
for (auto i : ms8)
cout << " " << i;
cout << endl;
}
Output
ms1 = 10 20 20 40
ms2 = 10 20
ms3 = 30
ms4 = 10 20 20 40
ms5 = 10 20
ms6 = 10
ms7 = 10 20
ms8= 1 2 3 4
Requirements
Header: <set>
Namespace: std