Ethics and Ownership — common mistakes

Be precise with your terminology. Do not use 'copyright' and 'plagiarism' interchangeably. An exam question might ask you to distinguish between them. Remember: copyright is a legal right, while plagiarism is an ethical breach of failing to attribute.

This is a common point of confusion. 'Freeware' means the software is free of charge, but it is proprietary and you cannot see or modify the source code. 'Free Software' (as defined by the Free Software Foundation) is about liberty, not price. It means you have the freedom to run, study, modify, and share the software and its source code. Free Software might be free of charge, or you might pay for it (e.g., for support or a compiled version).

It can be. Most content on Stack Overflow is licensed under a Creative Commons license (CC BY-SA). This license requires attribution, meaning you must state where you got the code from. Simply copying and pasting it into your project without giving credit is plagiarism and also violates the license terms. The best practice is to understand the code and adapt it, always crediting the source in your comments.

Copyright protects the specific expression of an idea (e.g., the exact lines of code), not the underlying idea or algorithm itself. While you can't copy the code directly, you can implement the same algorithm in your own way using your own code. However, some novel algorithms can be protected by a patent, which is a different form of IP that does protect the idea/process itself. Always check if a patent applies to a specific algorithm you are using.

No. Copyright has a limited term, though it is very long. In the UK and many other countries, it typically lasts for 70 years after the death of the creator. Once the copyright term expires, the work enters the 'public domain', meaning it is free for anyone to use for any purpose without permission.