public member function
<set>
std::set::empty
bool empty() const noexcept;
Test whether container is empty
Returns whether the set container is empty (i.e. whether its size is 0).
This function does not modify the container in any way. To clear the content of a set container, see set::clear.
Return Value
true if the container size is 0, false otherwise.
Example
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// set::empty
#include <iostream>
#include <set>
int main ()
{
std::set<int> myset;
myset.insert(20);
myset.insert(30);
myset.insert(10);
std::cout << "myset contains:";
while (!myset.empty())
{
std::cout << ' ' << *myset.begin();
myset.erase(myset.begin());
}
std::cout << '\n';
return 0;
}
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Output:
Iterator validity
No changes.
Data races
The container is accessed.
Concurrently accessing the elements of a set is safe.
Exception safety
No-throw guarantee: this member function never throws exceptions.
See also
- set::clear
- Clear content (public member function)
- set::erase
- Erase elements (public member function)
- set::size
- Return container size (public member function)