yes u can do it but u wont get course credits for it....meaning when coop is part of ur program u get credits for it meaning u take less subjects/courses. so without coop course it will be just like summer job which u can add to ur resume. If u get an internship u should do it even if it is not part of ur curriculum . just remember u have work restrictions though and u can only work for 20 hrs during regular sem and full time in holidays. i am assuming here that either u have work permit/work authorization or ur study permit allows u to work .