vector::size


public member function
size_type size() const;

Return size

Returns the number of elements in the vector container.

This is the number of actual objects held in the vector, which is not necessarily equal to its storage capacity. Vectors automatically reallocate their storage space when needed or when requested with member resize. To retrieve the current storage capacity of a vector you can call to its member capacity.

Parameters

none

Return Value

The number of elements that conform the vector's content.

Member type size_type is an unsigned integral type.

Example

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// vector::size
#include <iostream>
#include <vector>
using namespace std;

int main ()
{
  vector<int> myints;
  cout << "0. size: " << (int) myints.size() << endl;

  for (int i=0; i<10; i++) myints.push_back(i);
  cout << "1. size: " << (int) myints.size() << endl;

  myints.insert (myints.end(),10,100);
  cout << "2. size: " << (int) myints.size() << endl;

  myints.pop_back();
  cout << "3. size: " << (int) myints.size() << endl;

  return 0;
}


Output:
0. size: 0
1. size: 10
2. size: 20
3. size: 19


Complexity

Constant.

See also

vector::capacity Return size of allocated storage capacity (public member function)
vector::resize Change size (public member function)
vector::max_size Return maximum size (public member function)