Identifiers

Identifiers are names given to variables, functions and arrays. These are names which are user defined. They are made up by a combination of letters and digits. Normally an identifier should not be more than 8 characters long. The use of underscore is also permitted in identifiers.However, it is imperative that identifiers should begin with a letter.
Some example of identifiers are:
min1
max_temp
temp() etc.
C does not permit use of blank space, tabs, commas or special characters in identifiers.Thus:
min1
max*temp
12temp
are invalid identifier in C.