how do u keep these corporate companies frm stealing an app u developed nd pitched for dem

Why would you pitch it to them in the first place of you wanted to make it yourself?

Is the app already created or just an idea you pitched thus far?

If you've already created it:
If you created it on your own, not FOR the company specifically, the app is your intellectual property and they'd be idiots to try and steal it. I'm not sure where you're from but in the US that would be a huge lawsuit for them so long as you can prove the app is your creation that you did not make for the company under their direction.

If it's just an idea:
They can't duplicate your idea exactly, however unfortunately you can't stop people from mimicking your work, especially without a patent.

The best thing you can do is have them sign a non-disclosure or another legal document that could get them in hot water for stealing your work.

Best of luck!

thanks its an idea just been watchn a lot of movies wit ppl having gr8 ideas nd getn screwed