how to read mutliple lines of string into one variable using readln() in kotlin?

Question

example:

a variable

val str = readln().replace("[^A-Za-z0-9 ] \\s+".toRegex(),"").trim()

should read multiple lines of input value, input value will be like this

 heading
----------
topic1

topic2

or like this

heading
-------
a) topic1

b) topic2

input may contain special characters or tabs or spaces we need to remove them also

Answer 1

I don't know what your Regex is trying to do, but that's not really your question.

How do you know when the user has finished their input - a special word or an empty line?

Assuming an empty line, here's how you can get all the content

println("Enter something:")
var lines = ""
do {
    val line = readLine()
    lines += "${clean(line)}\n"
} while (!line.isNullOrBlank())
println("User input:\n$lines")

private fun clean(line: String?): String? {
    return line?.replace("[^A-Za-z0-9 ] \\s+".toRegex(),"")?.trim()
}