# Week 9 :::{topic} Learning goals - use `struct` and `union` - explain the trade-offs of using `struct` against array - explain the significance of data locality - implement self-referencing data structures - use `typedef` for `struct` - integrate and use an external library ::: :::{toctree} :maxdepth: 1 week09/balls-and-their-admirers week09/struct week09/data-locality week09/write-less-with-typedef week09/union week09/typeof week09/moving-a-shape :::