What does < ? : mean?

(cos(cangle) * (dist < radius ? dist : radius)) + sanaPad.X

What does < ? : mean, in this formula?

< means the usual, the ? mark is the thing that's special here - it's basically an "if" operator - so if dist is less than radius it uses dist, else it uses the radius.

https://www.scirra.com/manual/78/expressions more infos here

Oh yea, thank you. Now it becomes clear.