A
software bug is an error, flaw,
failure or
fault in a computer program or
system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. Most bugs arise from mistakes and errors made by people in either a program's
source code or its
design, or in frameworks and operating systems used by such programs, and a few are caused by
compilers producing incorrect code. A program that contains a large number of bugs, and/or bugs that seriously interfere with its functionality, is said to be
buggy or defective. Reports detailing bugs in a program are commonly known as bug reports, defect reports, fault reports, problem reports, trouble reports, change requests and so forth.