Background

This session introduces the tools you need to create and manipulate text files on the PC. Text files are just textual documents. You might compose a letter or message and save it on diskette in a text file. Subsequently you might edit it to correct mistakes or add more information. You might copy it from one diskette to another for backup purposes (in case one diskette gets damaged or lost). You might print it out or email it. You might delete it off your diskette when you no longer have any use for it.

We will be dealing with very basic so-called ASCII text documents. ASCII (American Standard Code for Information Interchange) is a standardised way of expressing text in electronic (binary) form. It essentially specifies a way of encoding each possible character as an 8-digit binary number, or byte. ASCII supports the lower and upper case alphabetic characters (a to z and A to Z), the digit characters 0 to 9, a variety of punctuation characters such as ; : . ? ( ) [ ] etc., and finally a collection of "special" characters such as + & * % etc.

ASCII provides roughly the same capability for representing text as used to be available with an old fashioned typewriter. ASCII does not support more advanced or complicated kinds of text such as accented characters, mathematical symbols, underlining, bolding, varying sized characters, etc. As such, ASCII might be regarded as pretty "primitive".

The great advantage of ASCII is that it really is a standard. ASCII encoded text files can be read and printed on virtually any computer system, and can be successfully transmitted through any email system. ASCII is a sort of "Lowest Common Denominator" of text file formats.

We will use ASCII files in this course for preparing lab reports, and for preparing program files (in the C programming language). C programs will, in effect, be ASCII files, and will be manipulated with the same tools as we manipulate any other ASCII files.