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Adjust Price With Toppings

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    Let's add the code now to our app.
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    We're going to start by calculating
    the base price of a drink.
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    The base price is composed of two parts.
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    The price of the coffee,
    which is $5 plus any toppings.
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    So $1 for whip cream,
    or $2 for chocolate.
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    We're going to take this base price, and
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    then we're going to multiply it
    by the quantity of cups ordered.
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    That will brings us to
    the total order price.
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    Let's calculate the price for
    a sample order,
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    where the user wants 3 cups of coffee
    with whipped cream, like this.
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    The goal of this course is not to test
    your math skills so let's walk through
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    the calculation together to make
    sure that you understand it.
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    The real goal will be for
    you to translate this logic into code.
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    In this sample order the user wants
    3 cups of coffee with whipped cream,
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    like this.
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    First, we can start off by calculating
    the base price of 1 cup of coffee.
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    We start with $5 for the coffee cup
    plus $1 for the whipped cream topping.
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    That brings us to $6 per cup.
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    Then, we need to find
    the total order price.
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    Since the user ordered 3 cups of coffee,
    we multiply $6 per cup times 3 cups.
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    That equals $18 total for
    the whole order.
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    In this sample order,
    we have 2 cups of coffee and
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    each cup has whipped cream topping and
    chocolate topping, like this and this.
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    First, we calculate
    the base price of 1 cup.
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    A cup of coffee costs $5,
    and then we add $1 for
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    whipped cream and $2 for chocolate.
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    That brings us to a total of 5,
    6, 7, 8, $8 per cup.
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    Then we find the total order price since
    the user ordered 2 cups of coffee.
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    We take the base price of $8 per
    cup of coffee times 2 cups and
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    that brings us to $16 total for
    the whole order.
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    This is what our app should look like.
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    We can enter in a name,
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    choose a whipped cream topping and
    then change the quantity to 3.
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    If we hit the Order button,
    we expect the price to change to $18.
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    And there it is.
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    This is exactly what we
    calculated earlier by hand.
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    If I add the chocolate topping,
    change the quantity to 2.
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    Then the total price becomes $16,
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    also just like we calculated where
    we have $8 per cup of coffee.
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    Now, go ahead and plan out the steps
    that you need to do in order to add this
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    functionality to our app.
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    I wrote down the price of
    the toppings here for reference.
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    And here's a screen shot of
    what the app should look like
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    with the adjusted price here.
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    After you've planned out the steps then
    go ahead and implement this in your app.
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    Then, can you tell me what
    method did you end up modifying?
タイトル:
Adjust Price With Toppings
概説:

13-18 Adjust Price With Toppings

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Video Language:
English
Team:
Udacity
プロジェクト:
UD837 - Android for Beginners
Duration:
02:28

English subtitles

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