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iOS Build a Vending Machine App in Swift 2.0 Using the Vending Machine Modeling the Vending Machine

Posted by Soner Güler
Soner Güler
16,505 Points

Item quantity control is wrong

You wrote the control like this:

guard item.quantity >= 0 else { throw VendingMachineError.OutOfStock }

But i think we should have controled the quantity of item with quantity that wanted.

For example customer may want 3 soda and program doesn't know that there is 3 Soda in the machine. We just sure that there is more than 0. It would be 1 or 2.

This is my opinion. I just want to be sure which method is right.

Taraj Shah
Taraj Shah
21,073 Points

Exactly. The same question I have. It is no point to check if it is greater than zero.

1 Answer

Kent Lou
PLUS
Kent Lou
Courses Plus Student 2,185 Points
Kent Lou
Kent Lou
Courses Plus Student 2,185 Points

Hi Soner and Taraj, you are absolutely right. What he wrote assumed customer is only purchasing one of the item selected, the proper check should be 

guard item.quantity >= quantity else {
    throw VendingMachineError.OutOfStock 
}

where item.quantity is the available stock and quantity is the input amount as required by customer