std::ifstream sets the eofbit at the point when the last item in the file is read, but it only happens when reading numerical types

Question

Suppose given a non-empty text file containing a list of numbers,

1 2 3 4 5

and we read them with std::ifstream into numerical types ( int , double , etc.) as well as char

int main()
{
    ifstream fs {"textfile.txt"};
    int val {0}; //read into ints
    for (int i{0}; i < 5; ++i)
    {
        //read five times
        fs >> val;
        cout << val << " is read. Current state of file stream: "
            << bitset<3> (fs.rdstate()) << endl; //check stream state after each read                        
    }
}

When read as numerical types, the program outputs:

1 is read. Current state of fs: 000
2 is read. Current state of fs: 000
3 is read. Current state of fs: 000
4 is read. Current state of fs: 000
5 is read. Current state of fs: 010

At the point when the last item of the file is read, the eofbit was set.

But the same thing doesn't happen when reading into char s.

int main()
{
    ifstream fs {"textfile.txt"};
    char ch {0}; //read into chars
    for (int i{0}; i < 5; ++i)
    {
        //read five times
        fs >> ch;
        cout << ch << " is read. Current state of file stream: "
            << bitset<3> (fs.rdstate()) << endl; //check stream state after each read                        
    }
}

which outputs:

1 is read. Current state of fs: 000
2 is read. Current state of fs: 000
3 is read. Current state of fs: 000
4 is read. Current state of fs: 000
5 is read. Current state of fs: 000

Why is this the case?

Answer 1

You get EOF when reading int s because the stream extraction operator for int tries to read till it finds either a whitespace or something unsuitable for an int . So it will try to read another char after the 5 was read, encounters the end of the file and the eofbit gets set.

In contrast, the stream extraction operator for char will only ever try to read one char so it won't encounter the end of the file. Try and read 6 char s from the file and you will also encounter EOF .