Streams and Files

Basic Concepts

Stream

a data type that processes characters

• Basically this is simple printing to the screen, input from the user, and manipulating files.
• Each language has specific requirements so it is better to read up on usage by yourself. Basic concepts are described here.

Output

sending out information

• I.e. printing to the screen.
• The default output device is the monitor.
• The main process of output is called Writing.

Input

receiving in information

• I.e. getting a value from the user.
• The default input device is the keyboard.
• The main process of output is called Reading.
• Looking at data but not reading it is called Peeking.

Linear Processing

the reading and/or writing to files in order of processing

• This is the basic way of processing streams. You process the characters as they come.

Random Access Processing

the reading and/or writing to files in any order

• This is not as common as liner processing and not quite standard. It is basically jumping around the stream. Think of a file rather than a keyboard. Instead of typing words one after another, imagine moving a cursor around a paragraph and typing words.

Files

File

a source of information

• These are used all the time. In general a three things are done in a file:
  1. the file is opened
  2. the file is processed
  3. the file is close
• Try opening savable files from other programs (try .cfg) in a word processor to see how they store data. Remember EDIT AT YOUR OWN RISK!!!

Text

a file that only has characters, ends in .txt

Data

a file that only has numbers, ends in .dat

ASCII File

a file that holds both numbers and letters

BOF

acronym for Beginning Of File

EOF

acronym for End Of File, more commonly used than BOF

Fail

a common term for when something went wrong in writing or reading a file

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