1. A data structure is a named group of data of different data types which is stored in a specific way and can be processed as a single unit. A data structure has well-defined operations, behaviour and properties.
Some common data structures are Stack, Lists, Queue, Linked lists and Tree.
2.
For copyright:
- It exists, without me doing anything to assert it, from the moment of creation.
- Unless explicitly assigned, or surrendered, it persists regardless of licence chosen for the software.
- It grants the creator very specific legal rights and remedies (although, these may vary by jurisdiction).
- Most forms of copyright have a defined duration (usually life + 'n' years).
- In an open source project, every contributor retains copyright in their own contributions.
For the Licence
- It is a legal document
- I have to explicitly choose, or create, the license. It does not apply automatically.
- It grants users of the software specific, and limited, rights.
- Unless stated in the Licence itself, or until it is revoked, it remains enforceable in perpetuity.