Multiplying variables and doubles in swift

I’m a designer looking into learning Swift and I’m a beginner.

I have no experience whatsoever.

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    Here is what I have so far.

    var billBeforeTax = 100
    var taxPercentage = 0.12
    var tax = billBeforeTax * taxPercentage
    

    I get the error:

    Binary operator ‘*’ cannot be applied to operands of type ‘Int’ and ‘Double’

    Does this mean I can’t multiply doubles?

    Am I missing any of the basic concepts of variables and doubles here?

    2 Solutions Collect From Internet About “Multiplying variables and doubles in swift”

    You can only multiple two of the same data type.

    var billBeforeTax = 100 // Interpreted as an Integer
    var taxPercentage = 0.12 // Interpreted as a Double
    var tax = billBeforeTax * taxPercentage // Integer * Double = error
    

    If you declare billBeforeTax like so..

    var billBeforeTax = 100.0
    

    It will be interpreted as a Double and the multiplication will work. Or you could also do the following.

    var billBeforeTax = 100
    var taxPercentage = 0.12
    var tax = Double(billBeforeTax) * taxPercentage // Convert billBeforeTax to a double before multiplying.
    

    You just have to cast your int variable to Double as below:

        var billBeforeTax = 100
        var taxPercentage = 0.12
        var tax = Double(billBeforeTax) * taxPercentage