People who write things are usually proud of what they have produced. Its quality reveals their ability, and its ownership may produce income or academic credit. It is wrong to take for yourself ownership of someone elses work, and wrong also to allow your own work to stand in for someone elses.
Your submission must be your own work; collaboration between students (unless specifically approved by the instructor) is an offence under the University of Torontos Code of Behaviour on Academic Matters. You will find the Code in the calendar of the Faculty of Arts and Science.
It is also an offence to permit another student to copy your own work. If you need advice on what is allowed and what is not, consult your instructor.
If you leave your account logged in on an unattended computer, we will assume that you meant to allow someone to copy your work. That is, if someone does copy your work, we will consider you to be guilty of an academic offence.
You must not copy any copyrighted software of the PC facility, or use software that has not been properly paid for. Software is very like books: you should not photocopy books without the publishers permission, because you would be taking away income the publisher and author are entitled to. Software is extremely easy to copy, but should be paid for all the same.
It is an offence under the Universitys Code of Student Conduct to possess property that is not your own. This includes unauthorized copies of communications programs and of the programming environment used in CSC 108.
You may, of course, copy files provided by your instructor for particular assignments.