Kotlin (Java) - Incrementation symbol ++ prefix and suffix - what is the exact meaning?

Asked Sep 20 '20 at 17:05

Active Sep 20 '20 at 17:11

Viewed 38 times

I am pasting the code below. The questions are written as a,b,c,d and e next to the codes. I could not try this by myself because I don't have an installed Android Studio currently. Can you explain?

        var pos = -1
        var ch = 0
        if (++pos < str.length) {        //a) here what is the value of pos?
                ch = str[pos].toInt()    //b) and here what is the value of pos?
            } else ch = -1

Next sample:

        var pos = -1
        var ch = 0
        if (pos++ < str.length) {        //c) here what is the value of pos?
                ch = str[pos].toInt()    //d) and here what is the value of pos?
            } else ch = -1
                                         //e) and at last what is the value of pos?

Edit: Kotlin documentation is lacking for explaining the difference, I couldn't understand from there.

edited Sep 20 '20 at 17:11

asked Sep 20 '20 at 17:05

Anthon Santhez

2

https://play.kotlinlang.org/ – IR42 Sep 20 '20 at 17:08
1

This post is about C, but it does a pretty good job explaining the difference: https://stackoverflow.com/q/7031326/2422776 – Mureinik Sep 20 '20 at 17:08
1

The code is the same in both snippets. Only the comments differ. Is that intended? Did you see https://kotlinlang.org/docs/reference/keyword-reference.html? – Robert Sep 20 '20 at 17:09
@IR42 thank you, I didn't know if such a website exists – Anthon Santhez Sep 20 '20 at 17:14
https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op1.html - scroll down to the prefix/postfix bit. Here's the Kotlin explanation: https://kotlinlang.org/docs/reference/operator-overloading.html#increments-and-decrements – cactustictacs Sep 20 '20 at 23:38
@cactustictacs thanks, I already got it:) – Anthon Santhez Sep 22 '20 at 17:23

Kotlin (Java) - Incrementation symbol ++ prefix and suffix - what is the exact meaning?

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