C++ Set Library - empty Function

Description

It returns whether the set container is empty.

Declaration

Following are the ways in which std::set::empty works in various C++ versions.

C++98

bool empty() const;

C++11

bool empty() const noexcept;

Return value

It returns whether the set container is empty.

Exceptions

It never throws exceptions.

Time complexity

Time complexity is contstant.

Example

The following example shows the usage of std::set::empty.

#include <iostream>
#include <set>

int main () {
   std::set<int> myset;

   myset.insert(0);
   myset.insert(10);
   myset.insert(20);

   std::cout << "myset contains:";
   while (!myset.empty()) {
      std::cout << ' ' << *myset.begin();
      myset.erase(myset.begin());
   }
   std::cout << '\n';

   return 0;
}

The above program will compile and execute properly.

myset contains: 0 10 20