C++ stack create

#include <iostream>
#include <stack>
#include <queue>

using namespace std;

void StackDemo(){
    stack<int, vector<int> > MyStack;

    MyStack.push(5);//from   ww  w . j a va2 s. co m
    MyStack.push(10);
    MyStack.push(15);
    MyStack.push(20);
    cout << MyStack.top() << endl;

    MyStack.pop();
    cout << MyStack.top() << endl;

    MyStack.pop();
    MyStack.push(40);
    cout << MyStack.top() << endl;

    MyStack.pop();
}

void QueueDemo()
{
    queue<int> MyQueue;

    MyQueue.push(5);
    MyQueue.push(10);
    MyQueue.push(15);
    cout << MyQueue.front() << endl;

    MyQueue.pop();
    cout << MyQueue.front() << endl;

    MyQueue.pop();
    MyQueue.push(40);
    cout << MyQueue.front() << endl;

    MyQueue.pop();
}

int main()
{
    StackDemo();
    QueueDemo();
    return 0;
}