The function of software architecture in programming projects is to define the structure and organization of the software system. It outlines the relationships between various components, including modules, libraries, and services, which ensures scalability, maintainability, and performance. A well-designed architecture serves as a blueprint for development, guiding developers through their tasks while enabling better collaboration among teams. Additionally, it addresses both functional and non-functional requirements, ensuring that the software meets user needs and adheres to quality standards, ultimately leading to successful project outcomes.