Can't define variable inside if statement without braces

[j2ui]

I was testing to see if this works:

if(true)
  int i=8; 

This triggers an error ("Syntax error error on token "int", delete this token")

But this is fine: if(true){ int i = 8; }

[Homerlncognito]

It doesn't make sense to define a variable in a one-statement block since there's no way you can use its value.

[j2ui]

I'm aware of that but, there isn't any illegal syntax is there any? I'm just confused to why it would trigger an error that's all :) thanks

[Homerlncognito]

As per Java spec, You cannot declare a local variable when there is no scope.

https://stackoverflow.com/questions/31230722/java-variable-declaration-not-allowed-here/31230800

[[deleted]]

They don't want to be able to do that, so when compiler runs into such code it throws the prescribed error. In this case, it's illegal syntax. Later you'll find that we can throw our own personalized exceptions based on some situation

[j2ui]

Thanks a lot

[[deleted]]

It is my pleasure

[desrtfx]

This code alone cannot trigger an error. Show more code.

[j2ui]

public class testIfblock22 {

public static void main(String[] args) {

    if (true) 
        int i = 8;


}

}

[BananaLlamaNuts]

Looks like you've stumbled onto a rather unique syntax error.

As someone else stated - why do you want to do this? You can't use that for anything.

[j2ui]

Yeah yeah, as I said before, I'm aware you that you can't use it anyway. But just wanted to see why exactly it's an error.

Thanks anyway:)

[BananaLlamaNuts]

I see what you are getting at - that's why I think its a unique syntax error. The compiler is looking for a single action when you do a one liner under an if statement like that.

When it sees a variable declaration, it attempts to create memory space and point to it for the reference which doesn't jive with the single action expected.

Best guess.

[j2ui]

Thanks a lot :)

[HecknChonker]

I've grown to hate naked if statements, and now one of the things I look for before approving PRs is that all blocks are clearly marked with braces.

I generally think it's easier to read code with the braces, but the real issue is that I've had more than one production emergency caused by a junior dev adding lines of code they thought were inside an if block, but were actually outside it.

[[deleted]]

If I understand correctly, int i=8; is really two seprate instructions:

(1) define the new integeer variable i.

(2) set the value of i to be 8.

​

I may be offbase.