How to find an angle from three Points?

Question

C++ / C#

I have three points of type point, A,B,C. How to find the angle between AB and BC in code. I studied at school, I know trigonometry. I just want to know if there are already some ready-made solutions in the standard library or something like that.

Answer 1

There is hardly anything standard for points, but for vectors - here:
https://msdn.microsoft.com/en-us/library/system.wi...

Answer 2

Leveling the angle between two straight lines on the plane - here
Distance between points on the plane - here