Disclaimer: the below is derived from my readings; for "legal advice" consult a lawyer of appropriate competence.
1) Copyright registration
Provided that you are in one of the countries that has agreed to the Berne Convention on Copyrights, you (or possibly the University, it gets legally messy) already have copyrights for your code, and also for any special graphics elements of the design that are unusual and non-obvious. The copyright exists from the time the code is created, even if there is no "Copyright" statement in the code, and continues for the usual durations or until copyright is given away by placing the work in the public domain. That copyright is legally enforceable through the courts.
The legal remedies you can request for violation of this level of copy vary with the country. In some countries, for example, you can claim $500 flat rate, and that essentially ends the case. If the country does not have that avenue, or you wish to claim more than that, or you wish to get injunctions or force the infringing copies to be destroyed, then you need to proceed through to trial. In such a case, the maximum damages for this level of copyright are still pretty modest, so considering legal expenses you would probably only go through this to either make a point or to get an injunction.
You can also, in countries that are signatories to the Berne Convention on Copyrights, register your copyright with an official registry. This requires paying an application fee and submitting a small number of copies of the work to the register. Upon successful registration through this mechanism, you become eligible to collect significantly higher damages, and violations after that become automatically considered "willful violations". On the other hand, you might have to regularly pay a fee to continue the official copyright registration.
Effectively you need to consider (A) organizational policies on such matters; and (B) whom is likely to engage in the violations. If you go after Joe Simple for copying off of a fellow student's legitimate copy, you probably are not going to get back enough to be worth the trouble and bad PR, but if you think a large company might copy and try to make a profit from it then it might be worth the trouble.
2) Mathworks re: source code
Mathworks explicitly disclaims having any rights to source code you wrote yourself using MATLAB or related products. You (or employer) have rights to all creative contributions you originate.
3) Mathworks re: compiled code
In return for paying for an authorized copy of MATLAB Compiler or MATLAB Coder, Mathworks licenses use of their library and technologies to you, with you having the right to distribute the compiled code for whatever fee you choose -- whether that be no cost, or minimal cost, or full commercial product pricing. Some restrictions may apply (USA export control laws must be satisfied.)
To see the Mathworks' licenses, go into MATLAB, press F1 to bring up the documentation browser, and then near the center bottom of any documentation page click on "Terms of Use" or equivalent wordings.
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