Weird stringstream behavior when extracting and inserting multiple times.

Question

Can someone help me understand this stringstream behavior?

stringstream temp;
temp << "342 1 ";
int a;
while (temp >> a) {
    cout << a << endl;
}
temp << "56" << " ";
temp >> a;
cout << a << endl;

Which outputs:

342
1
1

I would expect it to output

342
1
56

This was compiled in visual studios 2015.

Answer 1

After you have read the value 1, the next while will reach end-of-file and put the stream in an error state. Any further reads will then fail, and leave a unchanged.

You can clear the error state by calling temp.clear() .