Difference between Java and Kotlin for-loop syntax

I recently started learning Kotlin and for-loop syntax of Kotlin is different from Java.

**How would I duplicate the following Java for loop in Kotlin?
**

void funa(int a){
  for(int i = 0; a >= 1024; i++){
    a /= 1024;
  }
  System.out.println("val " + a + " stesps " + i)
}

I know i can do something like this

fun funa(a: Long){
    var b = a
    var i = 0;
    while (b>= 1024){ 
        b /= 1024
        i++
    }
}

but it looks realy stupid

Kotlin does not provide the for loop based on a counter, but only the for-each operation. In many cases we can replace traditional loops with a for-each over a range, for example:

for (i in 0..8) { }

Of course, in your case this is not possible. In this case we should use your suggested solution based on while.

Your Java code doesn't make sense--to be able to log i after the loop, you would have to declare i before the loop, so it would have to look like:

int i = 0;
for(; a >= 1024; i++){
    a /= 1024;
}
System.out.println("val " + a + " steps " + i);

That doesn't look any more or less stupid than:

var i = 0
while (a >= 1024) {
    a /= 1024
    i++
}
println("val $a steps $i")

It's just different syntax. It could be argued the Kotlin version is easier to read at the expense of number of lines, because it is more explicit and doesn't have the weird empty expression before the first ;.

It's a design decision that Kotlin doesn't have the for(;;) syntax. I think their reasoning is that it's confusing. It may not seem confusing if we've been using any C-syntax-based language for years, but to a brand new programmer, that syntax has a lot of individual elements to remember, contributing to a complex group of behaviors.

It's far more common for Java for-loops to simply be iterating something a pre-determined number of times. For that, you can use the repeat function:

repeat(10) { i ->
    println("Count $i")
}

Or if you are iterating a collection's indices:

for (i in list.indices) {
    println("Item $i is ${list[i]}")
}

</details>



# 答案3
**得分**: 0

诚实地说，你的提案已经看起来不错了。实际上，它比Java等效的更好，因为在Java中，你暗示计数器影响了循环条件，而事实并非如此。你只是想要计算步骤作为副作用。

---

在Kotlin中，你不能在这种用例中使用for循环，因为：

> for循环遍历任何提供迭代器的东西。[来源][1]

尽量不要过度设计，你已经有了适当的Kotlin代码。

[1]: https://kotlinlang.org/docs/control-flow.html#for-loops

<details>
<summary>英文:</summary>

Honestly, your proposal looks good already. It&#39;s actually better than the Java equivalent, because in that one you imply that the counter influences the loop condition which is not the case. You merely want to count the steps as a side-effect.

---

In Kotlin you cannot use a for loop for that use-case because:

&gt; for iterates through anything that provides an iterator. ([source][1])


Try not to overengineer things, you already have proper Kotlin code.

  [1]: https://kotlinlang.org/docs/control-flow.html#for-loops

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