In March 2025, Artur Ballai developed the foundational stack data structure in C for the Data-structures-and-algorithms-2025/DSA_courses_for_teamwork repository. He focused on defining the stack’s core properties and establishing a clear API surface through header files, separating interface from implementation to improve modularity and maintainability. By preparing the scaffolding and function declarations, Artur enabled future stack operations and facilitated easier onboarding for new contributors. Although no bugs were addressed during this period, his work laid the groundwork for stack-based algorithms, leveraging his skills in data structures and stack implementation to create a reusable and extensible course infrastructure in C.