Module 2 Lesson 12 Challenge (for loops)

Could someone tell me what’s the difference between these two? Thanks.
They both work.
I wrote the first one based on the tutorial of lesson 12
However, in the solution of lesson 12 challenge, it provided another syntax.

    for p in pizzaData { = UUID()

    for index in 0..<pizzaData.count {
        pizzaData[index].id = UUID()

If you left your model Pizza as a class then both will work. If you changed it to a struct (which is what Chris did in his solution) then only the second one will work.

The reason that the first one does not work on a struct is that when you use for p in pizzaData { the p is a let constant and let constants are immutable meaning they cannot be changed.

For some reason, leaving as a struct never worked for me (even with using the indexed loop). Changing to class did however work with both, as you said.