2.4 Variable Names
[This section corresponds to K&R Sec. 2.1]
Within limits, you can give your variables and functions any names you want. These names (the formal term is ``identifiers'') consist of letters, numbers, and underscores. For our purposes, names must begin with a letter. Theoretically, names can be as long as you want, but extremely long ones get tedious to type after a while, and the compiler is not required to keep track of extremely long ones perfectly. (What this means is that if you were to name a variable, say, supercalafragalisticespialidocious, the compiler might get lazy and pretend that you'd named it supercalafragalisticespialidocio, such that if you later misspelled it supercalafragalisticespialidociouz, the compiler wouldn't catch your mistake. Nor would the compiler necessarily be able to tell the difference if for some perverse reason you deliberately declared a second variable named supercalafragalisticespialidociouz.)
The capitalization of names in C is significant: the variable names variable, Variable, and VARIABLE (as well as silly combinations like variAble) are all distinct.
A final restriction on names is that you may not use keywords (the words such as int and for which are part of the syntax of the language) as the names of variables or functions (or as identifiers of any kind).
