File I/O in C++ works very similarly to normal I/O (with a few minor added complexities). There are 3 basic file I/O classes in C++: ifstream (derived from istream), ofstream (derived from ostream), and fstream (derived from iostream). These classes do file input, output, and input/output respectively. To use the file I/O classes, you . . . → Read More: 13.6 — Basic file I/O

Stream states

The ios_base class contains several state flags that are used to signal various conditions that may occur when using streams:

Flag Meaning goodbit Everything is okay badbit Some kind of fatal error occurred (eg. the program tried read past the end of a file) eofbit The stream has reached the end of . . . → Read More: 13.5 — Stream states and input validation

So far, all of the I/O examples you have seen have been writing to cout or reading from cin. However, there is another set of classes called the stream classes for strings that allow you to use the familiar insertions () operators to work with strings. Like istream and ostream, the string streams provide . . . → Read More: 13.4 — Stream classes for strings

In this section, we will look at various aspects of the iostream output class (ostream).

Note: All of the I/O functionality in this lesson lives in the std namespace. That means all I/O objects and functions either have to be prefixed with “std::”, or the “using namespace std;” statement has to be used.

The . . . → Read More: 13.3 — Output with ostream and ios