differString.kt

fun main () {
     val differ = differString("abc", "abd") { index, a, b ->
        a != b
    }
    println("differ : $differ")
}

fun differString(a: String, b: String, predicate: (index: Int, a: Char, b: Char) -> Boolean): Boolean {
    val org = a.toCharArray()
    val diff = b.toCharArray()
    if (org.size != diff.size) {
        return false
    }
    var idx = 0
    var different = false
    for (i in org) {
        if (predicate(idx, i, diff[idx])) {
            different = true
            break
        }
        idx++
    }
    return different
}