.empty()

The .empty() method returns true if the size of the vector is 0. Otherwise, if the vector has at least one element, it returns false. It is used to check if the vector contains any elements and is commonly used in conditional statements.

Syntax

The .empty() method requires no parameters and can be called on a vector using the following syntax:

myVector.empty();

• myVector: The vector on which the .empty() method is to be applied.

Example

The following example initializes a std::vector<int> named myvector and populates it with integers from 1 to 10. It then repeatedly removes the last element of the vector while it is not empty, adding each removed value to the variable sum. Finally, it prints the total sum of all elements:

#include <iostream>
#include <vector>

int main ()
{
  std::vector<int> myvector;
  int sum (0);

  for (int i=1;i<=10;i++) myvector.push_back(i);

  while (!myvector.empty())
  {
     sum += myvector.back();
     myvector.pop_back();
  }

  std::cout << "total: " << sum << '\n';

  return 0;
}

The code above produces the following output:

total: 55