Defines a stream to be used to read single-byte character data serially from a file. ifstream is a typedef that specializes the template class basic_ifstream for char.
There is also wifstream, a typedef that specializes basic_ifstream to read wchar_t double-wide characters. For more information, see wifstream.
The type is a synonym for template class basic_ifstream, specialized for elements of type char with default character traits. An example is
using namespace std;
// Dump the contents of the file to cout.
cout << infile.rdbuf();