is source files a design-time or run-time or both (design-time and run time)

Source files typically refer to the files containing the code written by developers, such as source code files written in languages like C++, Java, or Python. These files are primarily used and accessed during design-time, which is the development phase when programmers write, modify, and organize code.

During design-time, source files are essential for writing, editing, and compiling the code. Developers use integrated development environments (IDEs), text editors, or code editors to work with these files. IDEs provide features like syntax highlighting, code completion, and debugging tools, enhancing the development process.

However, source files also play a role during run-time, although indirectly. Before executing a program, the source code must be compiled or interpreted into an executable form, such as machine code or bytecode. This executable form is then executed, producing the output of the program at run-time.

So, while source files are primarily associated with the design-time phase, they are indirectly involved in the run-time phase by serving as the basis for generating the executable code that runs the program.