bugs的分类

来自Donald Knuth

A–Algorithm. The algorithm that the programmer designed is incorrect.
  A.off-by-one. The program makes a calculation that is off by one.
  A.logic. The algorithm has a logical flaw.
  A.validation. Variables are not properly checked to ensure they are valid. [*]
  A.performance. The algorithm has severe performance problems. [*]

D–Data. Data is not properly processed.
  D.index. An array is indexed into incorrectly.
  D.limit. Processing is done incorrectly at the beginning or end of the data.
  D.number. A bug related to how numbers are stored in memory.
  D.memory[*]. The program mismanages memory.

F–Forgotten. Statements are not executed in the intended order.
  F.init. A variable is not properly initialized.
  F.missing. A necessary statement is missing.
  F.location. A statement is in the wrong place.

B–Blunder. A simple mistake exists in the code.
  B.variable. The wrong variable name is used.
  B.expression. The calculation of an expression has a mistake.
  B.language. A bug specific to the syntax of the language.