input does not work properly

Hello guys
In the following code last input doesn't work
And the next line output prints some negative garbage value
why :confused:
thank you

Code:

---

// Test.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include "conio.h"

int _tmain(void)
{
        int sum= 0, val = 1 , a ;
        while(std::cin >> val){
                                                sum +=val;
                                                ++val;
        }
        std::cout << " Sum Of  Entery are " << sum << std::endl;
        std::cin >> a ;// does not  take any value
        std::cout<< a ;
        _getch();
        return 0;
}

---

Since the only way to exit your loop is to place the input stream into an error state you'll need to clear() the errors and empty the input buffer before you will be able to accept any more input from the stream.


Jim