Sybex CSG 17 - errata on page 68 - cast operator precedence

[Andrius Orlonas]

Cast operator has the highest precedence thus must be on the first row.

E.g.:

        double doubleValue = 10.5;
        int intValue;
        intValue = (int) doubleValue++;
        System.out.println("intValue: " + intValue); // Output: intValue: 10

[Liutauras Vilda]

Andrius Orlonas wrote:Cast operator has the highest precedence thus must be on the first row.

Can you elaborate a bit, what do you mean by "must be on the first row"?

The fact that given code snippet outputs 10 and not 11, I don't think it has anything to do with Cast operator precedence.

Try to put ++doubleValue as opposed to doubleValue++ and see what you get then.

Or I misunderstood you?

[Andrius Orlonas]

You might be right. I used a faulty secondary source for the operator precedence table and could not find the evidence that the cast indeed happens first.

[Paul Clapham]

Are you considering the possibility that

       intValue = (int) doubleValue++;

could be equivalent to

       intValue = ((int) doubleValue)++;

? You'll find that isn't valid Java code.

Which implies that the cast can't possibly be evaluated before the ++ operator.

[Andrius Orlonas]

Well, then there must be a mistake on the Enthuware OCP Java 11 book page 138 where the cast operator listed higher than the post increment op. That's where my confusion came from. I always considered Enthuware as an errata-free source.

[Paul Clapham]

There's always errors in published works. (We have a lot of posts on this site discussing those.) It's possible that this is one of them. I don't have the book so I can't comment about that, though.

[Campbell Ritchie]

Andrius Orlonas wrote:Cast operator has the highest precedence . . .

No, as people have already told you, it doesn't.
The whole idea of that sort of question is to remind you that although x++ has a higher precedence than casts, the post‑increment is hidden until the next time the variable is used. Also remember, if the value of x is outside the range -2147483648...2147483648exclusive, the increment will be annihilated by the cast. You will find all the gory details about casts in the Java Language Specification (=JLS).

[Paul Anilprem]

Andrius Orlonas wrote:Well, then there must be a mistake on the Enthuware OCP Java 11 book page 138 where the cast operator listed higher than the post increment op. That's where my confusion came from. I always considered Enthuware as an errata-free source.

Yes, that is a mistake. We apologize for the error. It has now been added to the errata. Will be fixed in the next iteration.