Answer 1

You have an unlimited amount of possible errors. You can even define your own in order to handle them (you would call them exceptions).

Programming errors are split into two categories: compile errors and runtime errors.

Compile errors are errors with your syntax, your variables, your function calls, etc. They are detected by the compiler and need to be fixed before the program can run at all.

Runtime errors are errors in your program's logic, in its algorithms. These errors aren't usually detected by the compiler, and the program will run. However, runtime errors will stop your program cold if not handled. An example of a runtime error would be a segmentation fault, which is pretty bad.

In general runtime errors are harder to identify because the compiler doesn't do it for you. That is why we invented debuggers.