Discover tips and techniques for using the Crop tool in Photoshop in this free video (Using the Crop Tool), from Photoshop CC 2017 Essential Training: The Basics on Lynda.com.
I have a copy of photoshop cc 2017 but on toolbar lefthand side there is no crop tool. I have seen your video but on my copy crop is missing.
Hmmm. Did you try resetting the tools? If so, I would try resetting the preferences next.