45 lines
1.9 KiB
Markdown
45 lines
1.9 KiB
Markdown
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Now that the cashier can scan items, the next step will be to have different items which take different amount of time.
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## Model
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In our model we now not only have to track the amount of items, but also the type. The items of the customer are stored in the ``CustomerItems`` array.
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You could have stored each item type as a different number, but this gets confusing and hard to maintain. Thats why we used an enum. We talk about how enums work later.
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To model the time each of these item needs, we have an array ``Time``, which associates with each item type a unique time.
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Now that items take different amounts of time, it gets interessting how long the whole scanning process took. For that we update the time in the variable ``TimePassed``.
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The time is counted in secconds.
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## Knowledge
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Know back to how enums work. An enum is a way to declare new types. In the background it only binds a number to a name. This makes your code more readable and easier to change,
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because the numbers are automatically generated. It doesn't matter if you add one member or delete one or change the order.
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Here is an example of an enum for food types.
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typedef enum
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{
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Burger,
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Pizza,
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Steak,
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Salad,
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Porkchop,
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Food_type_count,
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}food;
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The last line ``Food_type_count`` is a nice trick to get the amount of members of an enum. This only works because the compiler, the program which translates your code into machine readable code,
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just counts up the numbers. In this case Burger is 0 and Pizza is 1 ... and Food_type_count is 5;
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You could then use this for example to associate a kcal-value to them with an array.
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food kcal[Food_type_count];
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kcal[Burger] = 600;
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kcal[Salad] = 150;
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etc.
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This may not be the most elegant solution, but it is a pretty simple one.
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## Task
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Your task is to implement the items enum and update the amount of time depending on the scanned item.
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