In the context of Agile software development, when a programmer begins writing the first version of a program after receiving requirements from customers, they are engaging in the Implementation phase. This phase is characterized by the actual coding or development of the software, where the focus is on turning the design and analysis work into a working product. It's a part of the iterative process where developers create, test, and refine the software in successive iterations.
The Agile approach emphasizes incremental development and frequent feedback, with each iteration resulting in a potentially shippable product increment. The Implementation phase is where these increments are built, and it typically follows the Design phase, where the system's architecture and components are planned out.
References: The information aligns with the key stages of the Agile Development Life Cycle, which includes the phases of Concept, Inception, Iteration (Implementation), Testing, Release, and Review12.