What does a programmer do?

A programmer primarily works with programming languages to write code that instructs computers to perform specific tasks. This involves using various programming languages, such as Python, Java, or C++, to create software applications, algorithms, and other digital solutions. By writing code, the programmer translates requirements into a language that the computer can understand and execute. This role is central to the development of software, enabling everything from basic applications to complex systems.

The other options reflect aspects of technology that are not directly tied to the core responsibilities of a programmer. For instance, writing books on programming pertains to education and knowledge sharing rather than coding itself. Testing code is a crucial aspect of software development but is typically a distinct role, often filled by quality assurance professionals rather than programmers. Designing computer hardware falls under the domain of hardware engineers, who focus on the physical components of computers and other devices, which contrasts with the software-centric focus of programming.