I have a School class which includes avl trees: one for students, another for emptyClasses, and another for nonEmptyclasses.

The function I’m struggling with looks like this: (status is an enum such that 0=succes,1=allocation_error,3=failure,4=invalid=input):

Status leave_class(int studentId){
   //check validity of input
   try{
      if(numStudents==1){
         #remove class from nonEmptyClasses
         #add class to emptyClasses
      }
      Class->removeStudent(studentId)
   }
   catch(...){
      Return status::allocation_error
   }
   Students->leave() //this line changes student fields to ints of 0 and nullptr for pointers
   Return status::successs
}

The 3 actions in the try block could throw exceptions/errors, but then in the catch block if I try to reverse the error that happened then the reversing process could also be prone to the same errors.

For example, if I succeeded in removing a class from nonEmptyClasses and failed to add it in the emptyClasses, I have to reverse the removal which could also end up with an error.

I thought of separating the actions into multiple functions, or using mltiple try blocks, but I keep going back to square 1.

Any recommendations?