Kotlin String to ULong-CodePudding

I'm using Kotlin on Linux (kotlinc-jvm 1.7.21)

I would like to store a large number in a variable. So I found ULong to store 64 bits numbers. My number in binary is : 1111100001111100001111100001111110001111110001111110001111110001. This is 64 bits long, so just under the limit of a ULong variable. However, when I try to convert it from String to ULong,

var myLargeNumber = "1111100001111100001111100001111110001111110001111110001111110001".toULong()

I have the error :

Exception in thread "main" java.lang.NumberFormatException: Invalid number format: '1111100001111100001111100001111110001111110001111110001111110001'

CodePudding user response：

myLargeNumber.toULong() will try to interpret the number in base 10. 1111100001111100001111100001111110001111110001111110001111110001 is a lot larger than the maximum ULong value of 18446744073709551615, so toULong() fails

To interpret the number as a binary number you can instead specify the radix:

fun main() {
  val myLargeNumber = "1111100001111100001111100001111110001111110001111110001111110001"
    .toULong(radix = 2) // treat the string as a base 2 number
  println(myLargeNumber)
  // output: 17905254523795399665
}