c++ - Resume reading from iostream::cin after Ctrl+Z (EOF)? ("ignore" doesn't work)

Question

Why does the outer loop in the following program terminate when we provide ctrl+z for the inner loop only?

#include<iostream>
int main()
{
    string s1,s2;

    while(cin >> s1)
    {
        cout<<"In loop1
";
        while(cin>>s2)
            cout<<"In loop 2
";
        cin.ignore();
    }
}

Answer 1

Hitting Ctrl+z (on Windows) closes the standard input stream. Once it's closed, it stays closed. It doesn't magically reopen once the inner loop is finished. There's just no reason why it would.