C++ STL Deque

#include<iostream>
#include<deque>
using namespace std;
int main()
{
    deque<int>a;
    int b;
    cout << "Enter Some Integer Number :: \n";
    do
    {
        cin >> b;
        a.push_back(b);
    }
    while(b);

    cout << endl << "Size of deque :: " << a.size() << endl;

    return 0;
}