A string is a group of characters, usually letters of the alphabet. In order to format your printout in such a way that it looks nice, has meaningful titles and names, and is aesthetically pleasing to you and the people using the output of your program, you need the ability to output text data. We have used strings extensively already, without actually defining them. A complete definition of a string is ‘a sequence of char type data terminated by a NULL character,’.

When C is going to use a string of data in some way, either to compare it with another, output it, copy it to another string, or whatever, the functions are set up to do what they are called to do until a NULL character (which is usually a character with a zero ASCII code number) is detected. You should also recall (from Module 813: Fundamental Programming Structures in C) that the char type is really a special form of integer – one that stores the ASCII code numbers which represent characters and symbols.

An array (as we shall discover shortly) is a series of homogeneous pieces of data that are all identical in type. The data type can be quite complex as we will see when we get to the section of this module discussing structures. A string is simply a special case of an array, an array of char type data. The best way to see these principles is by use of an example [CHRSTRG.C]

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