I/O basic knowledge

Neither C++ nor C has built input and output in the language. They use functions(C) or other I/O objects(C++) in language library.
C++ I/O class and head file
1. iofs stand for three head files <iostream> <fstream> and <sstream>. <iostream> includes <ios> automatically. They are three main header file you should includes in your C++ application.
2. three classes: iostream(streambuf), fstream(filebuf), stringstream(stringbuf)
3. clog is just like cerr, but it buffer it output.
4. C++ normally flushes the input buffer when you press enter. For output to the display, C++ program normally flushes the output buffer when you transmit a newline character, or reaches an input statement.
5. >> and << don’t need to format string, C++ will automatically, convert it, it’s better than printf and scanf in C language.
6. through inheritance, fstream and cin(cout) share the same usage. All the knowledge can be used directly in fstream. I like it the most.