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# std::unordered_set::empty

From cppreference.com
< cpp‎ | container‎ | unordered set

[edit template]

bool empty() const; |  | (since C++11)

Checks if the container has no elements, i.e. whether begin() == end().

### [edit] Parameters

(none)

### [edit] Return value

true if the container is empty, false otherwise

### [edit] Exceptions

`noexcept` specification:
noexcept

### [edit] Complexity

Constant.

### [edit] Example

[edit]

The following code uses `empty` to check if a std::unordered_set<int> contains any elements:

Run this code

    #include <unordered_set>
    #include <iostream>

    int main()
    {
        std::unordered_set<int> numbers;
        std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';

        numbers.insert(42);
        numbers.insert(13317);
        std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';
    }

Output:

    Initially, numbers.empty(): 1
    After adding elements, numbers.empty(): 0

### See also

size | returns the number of elements (public member function) [edit]

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Category:

- unconditionally noexcept