Difference between revisions of "Avoid encodings: Hungarian Notation"

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* '''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)
 
* '''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.
 
* '''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.
  
  
 
[[Category: Clean Code]]
 
[[Category: Clean Code]]

Revision as of 12:12, 27 January 2020

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.