<P> Some naming conventions are enforced at the language level as part of the language syntax which involves the format of valid identifiers . In almost all languages, variable names cannot start with a digit (0--9) and cannot contain whitespace characters . Whether or not punctuation marks are permitted in variable names varies from language to language; many languages only permit the underscore ("_") in variable names and forbid all other punctuation . In some programming languages, sigils (symbols or punctuation) are affixed to variable identifiers to indicate the variable's datatype or scope . </P> <P> Case - sensitivity of variable names also varies between languages and some languages require the use of a certain case in naming certain entities; Most modern languages are case - sensitive; some older languages are not . Some languages reserve certain forms of variable names for their own internal use; in many languages, names beginning with two underscores ("__") often fall under this category . </P> <P> However, beyond the basic restrictions imposed by a language, the naming of variables is largely a matter of style . At the machine code level, variable names are not used, so the exact names chosen do not matter to the computer . Thus names of variables identify them, for the rest they are just a tool for programmers to make programs easier to write and understand . Using poorly chosen variable names can make code more difficult to review than non-descriptive names, so names which are clear are often encouraged . </P> <P> Programmers often create and adhere to code style guidelines which offer guidance on naming variables or impose a precise naming scheme . Shorter names are faster to type but are less descriptive; longer names often make programs easier to read and the purpose of variables easier to understand . However, extreme verbosity in variable names can also lead to less comprehensible code . </P>

Finding a value for a variable is referred to as