Big 0

I'm just a student beginning to learn C++. I created this very simple 70 line program that will generate a text file with your choice of extension however may bytes you enter. I believe this could be used to permanently wipe hard drives if reused multiple times. Or just use up a shit-ton of hard drive space on a computer if you choose to do so.
I called it "Big 0" because it can generate a big file full of zeros.