A file ends with a special end-of-file character, or <eof>. Reading it will fail, and returns an EOF value (a negative integer).
End of line is represented by a special character '\n', which is processed normally. It is an "escape sequence" that start with '\'.
A data source or destination is often called an input or output stream. Files, monitors, and keyboards can be seen as streams.
System file pointers: stdin for keyboard input, stdout for normal output to and monitor, stderr for error message.
Place holders are used in input/output formats.
Files are decleared as pointers of FILE. An "empty" pointer has value NULL.
Example FIGURE 11.1: backup a text file.
Example: FIGURE 11.3, which uses function fwrite to write into a binary file. The corresponding input function is fread.