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Lana Wong
3,968 PointsWhat does hourlyEmployee Stand for?
In Line 43, it say: if let hourlyEmployee = employee as! HourlyEmployee.
What does hourlyEmployee stand for? Did we create a new constant, or just change the type of the instance "hourlyEmployee", created on Line 36?
1 Answer
Ian Billings
Courses Plus Student 7,494 PointsHi Lana,
The hourlyEmployee in line 35 is added to an array with salariedEmployee on line 38. Because elements of an array have to be of the same type, the compiler upcasts the two instances to their parent class, which is Employee. Therefore, functionality that is available to HourlyEmployee class objects aren't available to the first element of the array even though the underlying type is of HourlyEmployee. Therefore, what Pasan is doing is down casting the element back down to an HourlyEmployee type. As down casting can fail (could return nil) Pasan uses an if let to check that the downcast is successful before attempting to use HourlyEmployee specific functionality. So in the end, the hourlyEmployee on line 43 is the same as the one earlier, and he can use the same variable name because the second variable is only useable within the for loop.
Hope that makes sense,
Ian