[SOLVED] Please, could someone help! What's the problem here?

Question

https://code.sololearn.com/cPtsN1R6bMPn/?ref=app

Answer 1

Ipang , I think your'e wrong.
The NOT-null assertion operator (!!) converts any value to a NON-null type!
That's, why the interpreter can be sure, that this value never can be NULL.
So if you use this:
var word = readLine()!!
with an empty input (=null), the interpreter throws an exception. It's not possible, but null-save for the whole prog.
Or, you use it null-able like this:
var word = readLine()
Now you are able to make an empty input (=null) . But every time, you want to access this variable, you have to check it against NULL by your self, like this:

fun main(args: Array<String>) {
var word = readLine()
if (word != null) {
for(x in word) {
println(x)
}
}
}

Answer 2

Line 2:
Non-nullable input for variable <var>
Add !! to make it nullable

var word = readLine()!!

Answer 3

It works but why I must make it nullable? Ipang

Answer 4

I saw this message before I added the !!

"error: not nullable value
required to call an 'iterator()"' method on for-loop range
for(x in word){"

I thought about just adding those !!

And it turned out to be working, so I suggested you that also ...

Answer 5

Thank you for better insight Coding Cat 🙏

Answer 6

https://kotlinlang.org/docs/null-safety.html#the-operator

Answer 7

Thanks a lot Coding Cat [Mouse searching]
Your code is also working :)