Defect:

Defect is any flaw in the software system,when there is a difference between expected result and actual result.

Defect can be classified into three categories:

1. Wrong
2. Extra
3. Missing

Wrong: The software does something that the product specification says it should not do.

Extra: The software does something that the product specification does not mention.

Missing: The software doesn't do something that the product  specification does not mention but system(software) should do.

• If product is difficult to understand,hard to use and slow this is also categories as defect.

Defects are introduced  not only due to coding errors but due to any of the following reasons:

Examples of Defects:

• User gives wrong/incomplete requirements
• Analyst interprets requirement incorrectly
• Requirements are not recorded correctly
• Design specifications are incorrect
• Incorrect Program specification
• Coding errors
• Data entry errors
• Error in testing: fail to detect existing errors
• Mistakes in error correction