View source for Avoid encodings: Hungarian Notation

Java programmers don’t need type encoding. Objects are strongly typed, and editing
environments have advanced such that they detect a type error long before you can run a
compile! So nowadays HN and other forms of type encoding are simply impediments.
They make it harder to change the name or type of a variable, function, or class. They
make it harder to read the code. And they create the possibility that the encoding system
will mislead the reader.

Examples of Hungarian Notation:

* '''lAccountNum''' : variable is a long integer ("l");
* '''arru8NumberList''' : variable is an array of unsigned 8-bit integers ("arru8");
* '''bReadLine(bPort,&arru8NumberList)''' : function with a byte-value return code.
* '''strName''' : Variable represents a string ("str") containing the name, but does not specify how that string is implemented.
* '''rwPosition''' : variable represents a row ("rw");
* '''usName''' : variable represents an unsafe string ("us"), which needs to be "sanitized" before it is used (e.g. see code injection and cross-site scripting for examples of attacks that can be caused by using raw user input)
* '''szName''' : variable is a zero-terminated string ("sz"); this was one of Simonyi's original suggested prefixes.
* '''pX''' is a pointer to another type X; this contains very little semantic information.
* '''d''' is a prefix meaning difference between two values; for instance, dY might represent a distance along the Y-axis of a graph, while a variable just called y might be an absolute position. This is entirely semantic in nature.
* '''sz''' is a null- or zero-terminated string. In C, this contains some semantic information because it is not clear whether a variable of type char* is a pointer to a single character, an array of characters or a zero-terminated string.
* '''w''' marks a variable that is a word. This contains essentially no semantic information at all, and would probably be considered Systems Hungarian.
* '''b''' marks a byte, which in contrast to w might have semantic information, because in C the only byte-sized data type is the char, so these are sometimes used to hold numeric values. This prefix might clear ambiguity between whether the variable is holding a value that should be treated as a character or a number.

Examples related to type:

* '''bBusy''' : boolean
* '''chInitial''' : char
* '''cApples''' : count of items
* '''dwLightYears''' : double word (Systems)
* '''fBusy''' : flag (or float)
* '''nSize''' : integer (Systems) or count (Apps)
* '''iSize''' : integer (Systems) or index (Apps)
* '''fpPrice''': floating-point
* '''dbPi''' : double (Systems)
* '''pFoo''' : pointer
* '''rgStudents''' : array, or range
* '''szLastName''' : zero-terminated string
* '''u16Identifier''' : unsigned 16-bit integer (Systems)
* '''u32Identifier''' : unsigned 32-bit integer (Systems)
* '''stTime''' : clock time structure
* '''fnFunction''' : function name

* '''pszOwner''' : pointer to zero-terminated string
* '''rgfpBalances''' : array of floating-point values
* '''aulColors''' : array of unsigned long (Systems)


[[Category: Clean Code]]