如何用科特林解释

Question

    var num:Int? = null
    var vice:Float = 20.0f
    if (num?.toFloat()?:0.0f- vice < 0.0f)

当num值为0.0时，则返回false

val realNumFloat = num?.toFloat()?:0.0f if(realNumFloat - vice < 0.0f)

返回真实