In working for a private corporation, is there a legal amount of time, one must give to quit? I had thought 2 weeks was the time, however people say without a contract, one may give less

The law does not address this question. Unless you have a contract that specifically says otherwise, you may give as much or as little notice as you like.

Please note that your employer may accept your resignation effective any time and is not required to allow you to work out your notice. Your employer is not required to pay you for any time you did not work, EVEN IF you gave notice that you were not allowed to work.

For most employers, you could simply stop going to work or walk off the job and suffer no legal problems as a result.

Don't expect the company to give you a good reference to prospective employers if you do either.

Two weeks notice is the general rule. For some folks, less notice will be okay, if they are easily replaced.

As pointed out above, some employers will walk you right off the premises even with the two weeks notice. This is not necessarily bad for you. They just don't want to risk having you around and causing problems. You might be able to get unemployment benefits for the two weeks you were willing to work should they do that to you.