Why is it important to write comments when coding a program?

Writing comments in code is crucial because it enhances the readability and maintainability of the code. When a developer revisits their own code after some time, or when a new developer is working on the same project, comments provide clear explanations of what specific code sections do, why certain decisions were made, and how to use or modify that code effectively. This documentation is invaluable, as it can significantly reduce the time and effort needed to understand complex logic, troubleshoot issues, or implement new features. Comments can convey the intent behind the code, which may not be immediately apparent from the code itself, thus facilitating better collaboration among developers.

The other reasons provided, such as increasing execution speed, encrypting code, or serving as a backup, do not accurately reflect the purpose of comments in coding. Comments do not impact the performance of a program, do not provide security against unauthorized access, and do not function as a means of backup for code. Their primary role is to communicate information about the code itself, making them an essential practice in software development.