Type mismatch: inferred type is Double but Float was expected (using Kotlin by the way)-CodePudding

The problem: So, obviously 3.0 can be considered a float. But for some reason Kotlin sees it as a double. This makes no sense to me. Could somebody tell me why Kotlin sees the number 3.0 as a double, rather than a float? Thanks!

fun main(){
    val num = 3.0
    random(num)
}

fun random(num: Float){
    print(num)
}

Note This is the online IDE that I was using. https://developer.android.com/training/kotlinplayground

CodePudding user response：

Because you did not type annotate it.

Double is a double-precision floating point number. (64bit)
Float is a single-precision floating point number. (32bit)

The default is the first because you're likely to find less unexpected bugs due to insufficient precision.

You may specify 3.0F, 3.0f to make that a Float or val number: Float = 3.0 should also hint the compiler that you want to deal with a 32bit floating-point number