What is a comment in source code used for?

A comment in source code is used to explain what parts of a program do, making it easier for other programmers (or even the original programmer at a later date) to understand the logic and purpose behind specific sections of the code. By providing descriptive notes, comments help clarify the function and operation of various processes, algorithms, or data structures within the code. This can be vital for maintenance, debugging, and collaborative work where multiple programmers may be involved.

Comments are not executed as part of the program; they serve solely as annotations without affecting the program's functionality. This distinguishes them from additional tasks such as executing code, creating variables, or defining functions, which are essential actions that directly contribute to the execution of a program. Therefore, using comments effectively enhances code readability and facilitates better communication among developers.