public member function
<stack>

std::stack::empty

bool empty() const;
Test whether container is empty
Returns whether the stack is empty: i.e. whether its size is zero.

This member function effectively calls member empty of the underlying container object.

Parameters

none

Return Value

true if the underlying container's size is 0, false otherwise.

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
 
// stack::empty
#include <iostream>       // std::cout
#include <stack>          // std::stack

int main ()
{
  std::stack<int> mystack;
  int sum (0);

  for (int i=1;i<=10;i++) mystack.push(i);

  while (!mystack.empty())
  {
     sum += mystack.top();
     mystack.pop();
  }

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

  return 0;
}

The example initializes the content of the stack to a sequence of numbers (form 1 to 10). It then pops the elements one by one until it is empty and calculates their sum.

Output:
total: 55

Complexity

Constant (calling empty on the underlying container).

Data races

The container is accessed.

Exception safety

Provides the same level of guarantees as the operation performed on the container (no-throw guarantee for standard container types).

See also

stack::size
Return size (public member function )