Help me testing my program

Question

I recently made a new simple program that approximates the root of polynomial equation of any degree. I don't know if mathematical error is in my program now, so I hope you to test my program. Thanks in advance.

-If you found error, please write coefficients and result in comment.

+EDIT+
For whom doesn't know how to use this program, here is the way to use:
1. Just put coefficients in order.(and a non-number letter)
2. Then the program automatically determines the degree and gives you the roots!

+Feedbacks are welcome!

https://code.sololearn.com/cMR4UJtYJBv2/?ref=app

Answer 1

@anubhav Thanks for testing my program!