Within software languages we have the ability to store information in mail boxes i.e. memory slots which are given names to represent the box. The naming rules are governed by the type of information stored in that box. There are three types of information in C: - Char (a single character), Boolean (a logical test i.e. 1 or 0), and numerical (float or integer e.g. 1.00 or 1).The name used must be an alpha-numeric name starting with a letter e.g. PI or out1 etc. The definition of the string type is a complicated topic this is covered later in the C course. Within C all commands, variables, inputs etc are case sensitive, therefore always use lower case. Variables are required to be defined within C i.e.

  float number1;  Defines a variable  number1 as a floating point  number

  int number1;    Defines a variable  number1 as a integer number

  char number1;  Defines a variable  number1 are a character