Software Lifecycle

Each software product proceeds to a number of distinct stages, the software life cycle. These stages include

• Requirements engineering
• Software design?
• Software construction?
• Validation and verification?
  • Software testing
• Software deployment
• Software maintenance

Depending the software process used for the development of the software product, these stages may occurr in different orders, or frequency. In the classical waterfall process? the stages are applied sequentially. In extreme programming the stages are repeated in very short (days) intervals.