Are Kotlin data types built off primitive or non-primitive Java data types? : <p>I am new to Kotlin and was playing around with the data types. I took an <code>Int</code> type and then tried to cast it as a <code>Double</code> by saying <code>num as Double</code>, a call that is valid in java (non syntactically but you get the point). However, this failed, saying that Int cannot be cast to Double. I am assuming this is because it is built off the Integer class rather than the raw int data type. Am I correct, and what is the most efficient way to cast values? There is a <code>.toDouble()</code> function, but this seems inefficient and unwieldy. </p>
