Defensive programming is a form of defensive design intended to ensure the continuing function of a piece of software in spite of unforeseeable usage of said software. The idea can be viewed as reducing or eliminating the prospect of Murphy's Law having effect. Defensive programming techniques come into their own when a piece of software could be misused mischievously or inadvertently to catastrophic effect. Defensive programming is an approach to improve software / source code, in terms of:

• General quality - Reducing the number of software bugs and problems.
• Making the Source code comprehensive - the source code should be readable and understandable so it is approved in a code audit.
• Making the software behave in a predictable manner.