Hungarian Notation

language, convention A linguistic convention requiring one

or more letters to be added to the start of variable names

to denote scope and/or type.

Hungarian Notation is mainly confined to Microsoft Windows

programming environments, such as Microsoft C, C++ and

Visual Basic. It was originally devised by CharlesSimonyi, a Hungarian, who was a senior programmer at

Microsoft for many years. He disliked the way that names in

C programs gave no clue as to the type, leading to frequent

programmer errors.

According to legend, fellow programmers at Microsoft, on

seeing the convoluted, vowel-less variable names produced by

his scheme, said, "This might as well be in Greek - or even

Hungarian!". They made up the name "Hungarian notation"

(possibly with "reverse Polish notation" in mind).

Hungarian Notation is not really necessary when using a modern

strongly-typed language as the compiler warns the

programmer if a variable of one type is used as if it were

another type. It is less useful in object-orientedprogramming languages such as C++, where many variables are

going to be instances of classes and so begin with "obj".

In addition, variable names are essentially only comments,

and thus are just as susceptible to becoming out-of-date and

incorrect as any other comment. For example, if a signed

short int becomes an unsigned long int, the variable

name, and every use of it, should be changed to reflect its

new type.

A variable's name should describe the values it holds. Type

and scope are aspects of this, but Hungarian Notation

overemphasises their importance by allocating so much of the

start of the name to them. Furthermore, type and scope

information can be found from the variable's declaration.

Ironically, this is particularly easy in the development

environments in which Hungarian Notation is typically used.

Simonyi's original monograph.

Microsoft VB Naming Conventions.

(2003-09-11)