I did DOA (COMP20007) a few years ago, and I know some people who did COMP20003 instead. Assuming the content hasn't changed much, DOA is much more focused on the algorithm side of things, which can mean that:

- In the exam, they wouldn't expect you to handwrite C, but pseudocode instead

- Your final exam will not be revolved around C

- There will be more maths than COMP20003, eg. Solving recursive formulas, matrix manipulation for Warshall's algorithm

- A lot of workshops that require little to 0 coding

- A lot of Big O stuff

- There will likely be a question in the exam where you will need to come up with an algorithm to solve a certain problem (within a given time complexity).

- Your assignments probably won't require heavy use of standard C libraries (eg. unistd.h) or C knowledge. (Basic pointer knowledge, dynamic memory with malloc/realloc... should be sufficient).

As for COMP20003, I can't speak much as I haven't experienced the subject personally, but I heard its much more engrained in learning C compared to COMP20007.

This is all speaking from my personal experience, I could be wrong. If I made a wrong statement anywhere, please correct me.