Edit

Share via

<unordered_set> operators

  • Article

operator!=

Tests whether the unordered_set object on the left side of the operator is not equal to the unordered_set object on the right side.

bool operator!=(const unordered_set <Key, Hash, Pred, Allocator>& left, const unordered_set <Key, Hash, Pred, Allocator>& right);

Parameters

left
An object of type unordered_set.

right
An object of type unordered_set.

Return Value

true if the unordered_sets are not equal; false if they are equal.

Remarks

The comparison between unordered_set objects is not affected by the arbitrary order in which they store their elements. Two unordered_sets are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.

Example

// unordered_set_ne.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_set>
#include <iostream>
#include <ios>

int main()
{
    using namespace std;

    unordered_set<char> c1, c2, c3;

    c1.insert('a');
    c1.insert('b');
    c1.insert('c');

    c2.insert('c');
    c2.insert('a');
    c2.insert('d');

    c3.insert('c');
    c3.insert('a');
    c3.insert('b');

   cout << boolalpha;
   cout << "c1 != c2: " << (c1 != c2) << endl;
   cout << "c1 != c3: " << (c1 != c3) << endl;
   cout << "c2 != c3: " << (c2 != c3) << endl;

    return (0);
}

Output:

c1 != c2: true

c1 != c3: false

c2 != c3: true

operator==

Tests whether the unordered_set object on the left side of the operator is equal to the unordered_set object on the right side.

bool operator==(const unordered_set <Key, Hash, Pred, Allocator>& left, const unordered_set <Key, Hash, Pred, Allocator>& right);

Parameters

left
An object of type unordered_set.

right
An object of type unordered_set.

Return Value

true if the unordered_sets are equal; false if they are not equal.

Remarks

The comparison between unordered_set objects is not affected by the arbitrary order in which they store their elements. Two unordered_sets are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.

Example

// unordered_set_eq.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_set>
#include <iostream>
#include <ios>

int main()
{
    using namespace std;

    unordered_set<char> c1, c2, c3;

    c1.insert('a');
    c1.insert('b');
    c1.insert('c');

    c2.insert('c');
    c2.insert('a');
    c2.insert('d');

    c3.insert('c');
    c3.insert('a');
    c3.insert('b');

   cout << boolalpha;
   cout << "c1 == c2: " << (c1 == c2) << endl;
   cout << "c1 == c3: " << (c1 == c3) << endl;
   cout << "c2 == c3: " << (c2 == c3) << endl;

    return (0);
}

c1 == c2: false
c1 == c3: true
c2 == c3: false

operator!= (multiset)

Tests whether the unordered_multiset object on the left side of the operator is not equal to the unordered_multiset object on the right side.

bool operator!=(const unordered_multiset <Key, Hash, Pred, Allocator>& left, const unordered_multiset <Key, Hash, Pred, Allocator>& right);

Parameters

left
An object of type unordered_multiset.

right
An object of type unordered_multiset.

Return Value

true if the unordered_multisets are not equal; false if they are equal.

Remarks

The comparison between unordered_multiset objects is not affected by the arbitrary order in which they store their elements. Two unordered_multisets are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.

Example

// unordered_multiset_ne.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_set>
#include <iostream>
#include <ios>

int main()
{
    using namespace std;

    unordered_multiset<char> c1, c2, c3;

    c1.insert('a');
    c1.insert('b');
    c1.insert('c');
    c1.insert('c');

    c2.insert('c');
    c2.insert('c');
    c2.insert('a');
    c2.insert('d');

    c3.insert('c');
    c3.insert('c');
    c3.insert('a');
    c3.insert('b');

   cout << boolalpha;
   cout << "c1 != c2: " << (c1 != c2) << endl;
   cout << "c1 != c3: " << (c1 != c3) << endl;
   cout << "c2 != c3: " << (c2 != c3) << endl;

    return (0);
}

c1 != c2: true
c1 != c3: false
c2 != c3: true

operator== (multiset)

Tests whether the unordered_multiset object on the left side of the operator is equal to the unordered_multiset object on the right side.

bool operator==(const unordered_multiset <Key, Hash, Pred, Allocator>& left, const unordered_multiset <Key, Hash, Pred, Allocator>& right);

Parameters

left
An object of type unordered_multiset.

right
An object of type unordered_multiset.

Return Value

true if the unordered_multisets are equal; false if they are not equal.

Remarks

The comparison between unordered_multiset objects is not affected by the arbitrary order in which they store their elements. Two unordered_multisets are equal if they have the same number of elements and the elements in one container are a permutation of the elements in the other container. Otherwise, they are unequal.

Example

// unordered_multiset_eq.cpp
// compile by using: cl.exe /EHsc /nologo /W4 /MTd
#include <unordered_set>
#include <iostream>
#include <ios>

int main()
{
    using namespace std;

    unordered_multiset<char> c1, c2, c3;

    c1.insert('a');
    c1.insert('b');
    c1.insert('c');
    c1.insert('c');

    c2.insert('c');
    c2.insert('c');
    c2.insert('a');
    c2.insert('d');

    c3.insert('c');
    c3.insert('c');
    c3.insert('a');
    c3.insert('b');

   cout << boolalpha;
   cout << "c1 == c2: " << (c1 == c2) << endl;
   cout << "c1 == c3: " << (c1 == c3) << endl;
   cout << "c2 == c3: " << (c2 == c3) << endl;

    return (0);
}

c1 == c2: false
c1 == c3: true
c2 == c3: false