Initial capacity of vector in C++

Question

What is the capacity() of an std::vector which is created using the default constuctor? I know that the size() is zero. Can we state t

Answer 1

Storage implementations of std::vector vary significantly, but all the ones I've come across start from 0.

The following code:

#include 
#include 

int main()
{
  using namespace std;

  vector normal;
  cout << normal.capacity() << endl;

  for (unsigned int loop = 0; loop != 10; ++loop)
  {
      normal.push_back(1);
      cout << normal.capacity() << endl;
  }

  cin.get();
  return 0;
}

Gives the following output:

0
1
2
4
4
8
8
8
8
16
16

under GCC 5.1 and:

0
1
2
3
4
6
6
9
9
9
13

under MSVC 2013.