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I don't why I get 'not a statement' error in the following code...

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  I don't why I get 'not a statement' error in the following code... Chad <cdalten@gmail.com> - 2011-10-04 11:16 -0700
    Re: I don't why I get 'not a statement' error in the following code... Patricia Shanahan <pats@acm.org> - 2011-10-04 11:33 -0700
      Re: I don't why I get 'not a statement' error in the following code... Chad <cdalten@gmail.com> - 2011-10-04 11:43 -0700
        Re: I don't why I get 'not a statement' error in the following code... markspace <-@.> - 2011-10-04 12:14 -0700
        Re: I don't why I get 'not a statement' error in the following code... Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-04 12:20 -0700
      Re: I don't why I get 'not a statement' error in the following code... Chad <cdalten@gmail.com> - 2011-10-04 14:55 -0700
        Re: I don't why I get 'not a statement' error in the following code... Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-04 15:09 -0700
          Re: I don't why I get 'not a statement' error in the following code... Chad <cdalten@gmail.com> - 2011-10-04 15:11 -0700
            Re: I don't why I get 'not a statement' error in the following code... Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-04 17:30 -0700
        Re: I don't why I get 'not a statement' error in the following code... Stanimir Stamenkov <s7an10@netscape.net> - 2011-10-05 01:19 +0300
        Re: I don't why I get 'not a statement' error in the following code... Patricia Shanahan <pats@acm.org> - 2011-10-04 22:16 -0700
          Re: I don't why I get 'not a statement' error in the following code... Chad <cdalten@gmail.com> - 2011-10-05 08:13 -0700
            Re: I don't why I get 'not a statement' error in the following code... Patricia Shanahan <pats@acm.org> - 2011-10-05 10:21 -0700
            Re: I don't why I get 'not a statement' error in the following code... Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-05 20:43 -0400
              Re: I don't why I get 'not a statement' error in the following code... markspace <-@.> - 2011-10-05 19:36 -0700
                Re: I don't why I get 'not a statement' error in the following code... Lew <lewbloch@gmail.com> - 2011-10-05 19:43 -0700
    Re: I don't why I get 'not a statement' error in the following code... Roedy Green <see_website@mindprod.com.invalid> - 2011-10-05 12:00 -0700

#8538 — I don't why I get 'not a statement' error in the following code...

public class hw1q3 {

    public static void main(String[] args) {
        Test a = new Test();
        a.showAllOne();
        a.showAllTwo();
        System.out.println("The value of x is " + Test.x); //I get x
is 2
        Test.x; //I get a compile error that says - not a statement
    }
}

class Test {

    public static final int w = 1;
    public static int x = 2;
    public final int y = 3;
    public int z = 4;

    public void showAllOne() {
        System.out.println("w is " + w);
        System.out.println("x is " + x);
        System.out.println("y is " + y);
        System.out.println("z is " + z);
    }

    public static void showAllTwo() {
        System.out.println("w is " + w);
        System.out.println("x is " + x);
        //System.out.println("y is " + y);
        //System.out.println("z is " + z);
    }
}


I don't get why 'Test.x;'  in main() isn't a variable. The expression
'Test.x' ends with a semicolon. So I just assumed it was a valid
statement. However, the java compiler tells me something different.
Ideas? Possible hints?

Chad

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#8539

On 10/4/2011 11:16 AM, Chad wrote:
...
> I don't get why 'Test.x;'  in main() isn't a variable. The expression
> 'Test.x' ends with a semicolon. So I just assumed it was a valid
> statement. However, the java compiler tells me something different.
> Ideas? Possible hints?

See the JLS,
http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.8

Only certain types of expressions can be turned into a statement by
adding a semicolon. They all have at least potential for side-effects at
the top level.

May I ask why you need to execute Test.x without doing anything with the
result?

Patricia

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#8540

On Oct 4, 11:33 am, Patricia Shanahan <p...@acm.org> wrote:
> On 10/4/2011 11:16 AM, Chad wrote:
> ...
>
> > I don't get why 'Test.x;'  in main() isn't a variable. The expression
> > 'Test.x' ends with a semicolon. So I just assumed it was a valid
> > statement. However, the java compiler tells me something different.
> > Ideas? Possible hints?
>
> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>
> Only certain types of expressions can be turned into a statement by
> adding a semicolon. They all have at least potential for side-effects at
> the top level.
>
> May I ask why you need to execute Test.x without doing anything with the
> result?
>

Because I was trying to figure out the error. The actual line of code
is something like

Test.x += x;

But when I stripped the line to

Test.x;

I got the same error.

Chad

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#8543

On 10/4/2011 11:43 AM, Chad wrote:

> Because I was trying to figure out the error. The actual line of code
> is something like
>
> Test.x += x;


What variable does the second "x" refer to here?

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#8545

On 10/4/11 11:43 AM, Chad wrote:
> On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>  wrote:
>> On 10/4/2011 11:16 AM, Chad wrote:
>> ...
>>
>>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
>>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
>>> statement. However, the java compiler tells me something different.
>>> Ideas? Possible hints?
>>
>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>> Only certain types of expressions can be turned into a statement by
>> adding a semicolon. They all have at least potential for side-effects at
>> the top level.
>>
>> May I ask why you need to execute Test.x without doing anything with the
>> result?
>>
>
> Because I was trying to figure out the error. The actual line of code
> is something like
>
> Test.x += x;
>
> But when I stripped the line to
>
> Test.x;
>
> I got the same error.
>
> Chad

"Test.x += x;" is not the same as "Test.x";

Also, "Test.x" is fine, but "x" (in class hw1q3) is not defined.

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#8548

On Oct 4, 11:33 am, Patricia Shanahan <p...@acm.org> wrote:
> On 10/4/2011 11:16 AM, Chad wrote:
> ...
>
> > I don't get why 'Test.x;'  in main() isn't a variable. The expression
> > 'Test.x' ends with a semicolon. So I just assumed it was a valid
> > statement. However, the java compiler tells me something different.
> > Ideas? Possible hints?
>
> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>
> Only certain types of expressions can be turned into a statement by
> adding a semicolon. They all have at least potential for side-effects at
> the top level.
>
> May I ask why you need to execute Test.x without doing anything with the
> result?
>

I still don't see why this expression can't be turned into a
statement.

Chad

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#8549

On 10/4/11 2:55 PM, Chad wrote:
> On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>  wrote:
>> On 10/4/2011 11:16 AM, Chad wrote:
>> ...
>>
>>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
>>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
>>> statement. However, the java compiler tells me something different.
>>> Ideas? Possible hints?
>>
>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>> Only certain types of expressions can be turned into a statement by
>> adding a semicolon. They all have at least potential for side-effects at
>> the top level.
>>
>> May I ask why you need to execute Test.x without doing anything with the
>> result?
>>
>
> I still don't see why this expression can't be turned into a
> statement.
>
> Chad
>
What does "Test.x;" mean to you? If it successfully compiled, what would 
you expect that it does?

Test.x is a variable reference, you either need to read it or write it.

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#8550

On Oct 4, 3:09 pm, Daniel Pitts <newsgroup.nos...@virtualinfinity.net>
wrote:
> On 10/4/11 2:55 PM, Chad wrote:
>
>
>
> > On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>  wrote:
> >> On 10/4/2011 11:16 AM, Chad wrote:
> >> ...
>
> >>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
> >>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
> >>> statement. However, the java compiler tells me something different.
> >>> Ideas? Possible hints?
>
> >> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>
> >> Only certain types of expressions can be turned into a statement by
> >> adding a semicolon. They all have at least potential for side-effects at
> >> the top level.
>
> >> May I ask why you need to execute Test.x without doing anything with the
> >> result?
>
> > I still don't see why this expression can't be turned into a
> > statement.
>
> > Chad
>
> What does "Test.x;" mean to you? If it successfully compiled, what would
> you expect that it does?
>
> Test.x is a variable reference, you either need to read it or write it.

I thought it did the same thing as something like a.x

Chad

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#8552

On 10/4/11 3:11 PM, Chad wrote:
> On Oct 4, 3:09 pm, Daniel Pitts<newsgroup.nos...@virtualinfinity.net>
> wrote:
>> On 10/4/11 2:55 PM, Chad wrote:
>>
>>
>>
>>> On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>    wrote:
>>>> On 10/4/2011 11:16 AM, Chad wrote:
>>>> ...
>>
>>>>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
>>>>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
>>>>> statement. However, the java compiler tells me something different.
>>>>> Ideas? Possible hints?
>>
>>>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>>>> Only certain types of expressions can be turned into a statement by
>>>> adding a semicolon. They all have at least potential for side-effects at
>>>> the top level.
>>
>>>> May I ask why you need to execute Test.x without doing anything with the
>>>> result?
>>
>>> I still don't see why this expression can't be turned into a
>>> statement.
>>
>>> Chad
>>
>> What does "Test.x;" mean to you? If it successfully compiled, what would
>> you expect that it does?
>>
>> Test.x is a variable reference, you either need to read it or write it.
>
> I thought it did the same thing as something like a.x
>
> Chad

Okay, what does "a.x" mean to you? Same question.

a.x; will not compile.

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#8551

Tue, 4 Oct 2011 14:55:12 -0700 (PDT), /Chad/:
> On Oct 4, 11:33 am, Patricia Shanahan wrote:
>
>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>> Only certain types of expressions can be turned into a statement by
>> adding a semicolon. They all have at least potential for side-effects at
>> the top level.
>>
>> May I ask why you need to execute Test.x without doing anything with the
>> result?
> 
> I still don't see why this expression can't be turned into a
> statement.

Because it doesn't match any of the syntax constructions given in 
the Java Language Specification referenced above (learn to read):

        LocalVariableDeclarationStatement
        ClassDeclaration
        Statement

Your statement |Test.x;| is obviously not a local variable 
declaration nor class declaration, further:

Statement:
        StatementWithoutTrailingSubstatement
        LabeledStatement
        IfThenStatement
        IfThenElseStatement
        WhileStatement
        ForStatement

Yours is none of labeled, if-then, if-then-else, while or for 
statement, so:

StatementWithoutTrailingSubstatement:
        Block
        EmptyStatement
        ExpressionStatement
        AssertStatement
        SwitchStatement
        DoStatement
        BreakStatement
        ContinueStatement
        ReturnStatement
        SynchronizedStatement
        ThrowStatement
        TryStatement

The only posibility here is expression statement:

ExpressionStatement:
        StatementExpression ;

StatementExpression:
        Assignment
        PreIncrementExpression
        PreDecrementExpression
        PostIncrementExpression
        PostDecrementExpression
        MethodInvocation
        ClassInstanceCreationExpression

Which of the given above should match your statement?  Yours is 
neither assignment nor pre-increment, nor pre-decrement, nor 
post-increment, nor post-decrement, nor method invocation, nor 
class instance creation.

-- 
Stanimir

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#8553

On 10/4/2011 2:55 PM, Chad wrote:
> On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>  wrote:
>> On 10/4/2011 11:16 AM, Chad wrote:
>> ...
>>
>>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
>>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
>>> statement. However, the java compiler tells me something different.
>>> Ideas? Possible hints?
>>
>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>> Only certain types of expressions can be turned into a statement by
>> adding a semicolon. They all have at least potential for side-effects at
>> the top level.
>>
>> May I ask why you need to execute Test.x without doing anything with the
>> result?
>>
>
> I still don't see why this expression can't be turned into a
> statement.

Primarily, it is a matter of language definition, which is why I
included a link to the Java Language Specification.

Are you saying that you think it is valid according to the JLS, or are
you saying that you do not understand why the Java designers decided not
to permit it?

Patricia

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#8574

On Oct 4, 10:16 pm, Patricia Shanahan <p...@acm.org> wrote:
> On 10/4/2011 2:55 PM, Chad wrote:
>
>
>
>
>
> > On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>  wrote:
> >> On 10/4/2011 11:16 AM, Chad wrote:
> >> ...
>
> >>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
> >>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
> >>> statement. However, the java compiler tells me something different.
> >>> Ideas? Possible hints?
>
> >> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>
> >> Only certain types of expressions can be turned into a statement by
> >> adding a semicolon. They all have at least potential for side-effects at
> >> the top level.
>
> >> May I ask why you need to execute Test.x without doing anything with the
> >> result?
>
> > I still don't see why this expression can't be turned into a
> > statement.
>
> Primarily, it is a matter of language definition, which is why I
> included a link to the Java Language Specification.
>
> Are you saying that you think it is valid according to the JLS, or are
> you saying that you do not understand why the Java designers decided not
> to permit it?
>

I guess I don't understand why the Java designers decided not to
permit it.

Chad

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#8576

On 10/5/2011 8:13 AM, Chad wrote:
> On Oct 4, 10:16 pm, Patricia Shanahan<p...@acm.org>  wrote:
>> On 10/4/2011 2:55 PM, Chad wrote:
>>
>>
>>
>>
>>
>>> On Oct 4, 11:33 am, Patricia Shanahan<p...@acm.org>    wrote:
>>>> On 10/4/2011 11:16 AM, Chad wrote:
>>>> ...
>>
>>>>> I don't get why 'Test.x;'  in main() isn't a variable. The expression
>>>>> 'Test.x' ends with a semicolon. So I just assumed it was a valid
>>>>> statement. However, the java compiler tells me something different.
>>>>> Ideas? Possible hints?
>>
>>>> See the JLS,http://java.sun.com/docs/books/jls/third_edition/html/statements.html...
>>
>>>> Only certain types of expressions can be turned into a statement by
>>>> adding a semicolon. They all have at least potential for side-effects at
>>>> the top level.
>>
>>>> May I ask why you need to execute Test.x without doing anything with the
>>>> result?
>>
>>> I still don't see why this expression can't be turned into a
>>> statement.
>>
>> Primarily, it is a matter of language definition, which is why I
>> included a link to the Java Language Specification.
>>
>> Are you saying that you think it is valid according to the JLS, or are
>> you saying that you do not understand why the Java designers decided not
>> to permit it?
>>
>
> I guess I don't understand why the Java designers decided not to
> permit it.

I think to reduce source code that is pure decoration, with no
effect on the program as run.

A Java implementation is allowed to optimize, as long as it keeps both
any results that are used and any side effects. Evaluating Test.x has no
side effects, and the result is dead, so the entire statement would be
dead code which the implementation can, and ideally should, firmly ignore.

Patricia

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#8586

On 10/5/2011 11:13 AM, Chad wrote:
> [... concerning non-statements like `42;' ...]
>
> I guess I don't understand why the Java designers decided not to
> permit it.

     Java's designers chose to enshrine only some of C's infelicities.

     Here's another one they didn't perpetuate:

	String[] array = { "I", "am", "commutative" };
	String s = 1[array];

"Others will occur to your thought." -- Gandalf

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

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#8588

On 10/5/2011 5:43 PM, Eric Sosman wrote:
> On 10/5/2011 11:13 AM, Chad wrote:
>> [... concerning non-statements like `42;' ...]
>>
>> I guess I don't understand why the Java designers decided not to
>> permit it.
>
> Java's designers chose to enshrine only some of C's infelicities.
>
> Here's another one they didn't perpetuate:
>
> String[] array = { "I", "am", "commutative" };
> String s = 1[array];
>
> "Others will occur to your thought." -- Gandalf
>


#define static

Don't laugh I've seen it done.

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#8589

markspace wrote:
> #define static
> 
> Don't laugh I've seen it done.

That shit just makes me mad.

-- 
Lew

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#8579

On Tue, 4 Oct 2011 11:16:22 -0700 (PDT), Chad <cdalten@gmail.com>
wrote, quoted or indirectly quoted someone who said :

>public class hw1q3 {
Class name must start with capital letter.
See http://mindprod.com/jgloss/codingconventions.html

>
>    public static void main(String[] args) {
>        Test a = new Test();
>        a.showAllOne();
>        a.showAllTwo();
>        System.out.println("The value of x is " + Test.x); //I get x
>is 2
>        Test.x; //I get a compile error that says - not a statement
Test.x is a variable. You have to do something with it, e.g. pass it
as a parameter, add 1 to it. . 

>    }
>}
>
>class Test {
>
>    public static final int w = 1;
>    public static int x = 2;
>    public final int y = 3;
>    public int z = 4;
is real life you never expose your variables like that.  You use a
getter/setter.

>
>    public void showAllOne() {
>        System.out.println("w is " + w);
>        System.out.println("x is " + x);
>        System.out.println("y is " + y);
>        System.out.println("z is " + z);
>    }
>
>    public static void showAllTwo() {
>        System.out.println("w is " + w);
>        System.out.println("x is " + x);
>        //System.out.println("y is " + y);
>        //System.out.println("z is " + z);
>    }
>}
-- 
Roedy Green Canadian Mind Products
http://mindprod.com
It should not be considered an error when the user starts something
already started or stops something already stopped. This applies
to browsers, services, editors... It is inexcusable to 
punish the user by requiring some elaborate sequence to atone,
e.g. open the task editor, find and kill some processes.

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