Help, I have to put the discount on my code but I don't know how

My professor asked me to improvise my previous coding by giving 10% off the price to member and if there is a VIP member, his/her order will be done first, my code is working fine, but I don't know how to implement new code for the improvement

 
Give the code of your program so that we can solve it
Topic archived. No new replies allowed.