Syntax error on token "else" — how on earth?

Question

I'm learning Java the classic way — by playing around with Karel.

But I seem to have encountered a simple problem I can't solve even with the help of Google.

I'm getting an error in Eclipse saying there's a syntax error on the token "else", and that I should delete it.

How come? The syntax in the code block above the else statement is identical.

Here's my code:

public void run() {

    putBeeper();
    if(beepersPresent()){

        move();

    } while(frontIsClear()){
        move();
        putBeeper();
    } else if(facingEast()){

        turnLeft();
        move();

    }
        }

Wow people, do we really need 8 responses saying the same thing? — jn1kk, Nov 18 '11 at 18:52
@Skynorth To be fair to the answerers, 7 of 8 of them answered within the same minute, with the 8th not far behind. — Eric Wilson, Nov 18 '11 at 19:01
I usually delete or cancel my answer when there's a *better* duplicate been posted at the same time: http://meta.stackexchange.com/questions/15775/do-you-delete-your-own-answer-when-its-a-duplicate Most others also do that. It keeps the noise down. — BalusC, Nov 18 '11 at 19:10

stacker · Answer 1 · 2011-11-18T18:55:42.103

The else statement has to follow immediatly after the if, you have a while loop between them.

Since this was downvoted, more formal the relevant section of Java Language Specification

14.9 The if Statement The if statement allows conditional execution of a statement or a conditional choice of two statements, executing one or the other but not both.

IfThenStatement:
        if ( Expression ) Statement

IfThenElseStatement:
        if ( Expression ) StatementNoShortIf else Statement

IfThenElseStatementNoShortIf:
        if ( Expression ) StatementNoShortIf else StatementNoShortIf

The Expression must have type boolean or Boolean, or a compile-time error occurs.

score 3 · Answer 2 · answered Nov 18 '11 at 18:45

3

Because you're trying to say while() { } else {

Why else?

(Yes, I did just do that.)

answered Nov 18 '11 at 18:45

Brian Roach

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score 0 · Answer 3 · answered Nov 18 '11 at 18:44

0

Your else matches while, not if. Not entirely clear what you are trying to do there.

answered Nov 18 '11 at 18:44

K-ballo

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score 0 · Answer 4 · answered Nov 18 '11 at 18:44

0

Probably:

while(frontIsClear())

should be

else if(frontIsClear())

answered Nov 18 '11 at 18:44

Bhesh Gurung

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score 0 · Answer 5 · answered Nov 18 '11 at 18:45

0

What exactly are you trying to do here?

while(frontIsClear()){
        move();
        putBeeper();
    } else if(facingEast()){

        turnLeft();
        move();

While this.. else if that? Not possible.

answered Nov 18 '11 at 18:45

FailedDev

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score 0 · Answer 6 · answered Nov 18 '11 at 18:45

You put your else after a while, this is indeed a syntax error

Try that:

public void run() {
    putBeeper();
    if(beepersPresent()){
        move();
    } 
    while(frontIsClear()){
        if (facingEast()) {
            turnLeft();
        }
        move();
        putBeeper();
    }
}

score 0 · Answer 7 · answered Nov 18 '11 at 18:45

0

Really quite simple.

Your if lasts between the { and }. The else has to be exactly afterwards.

Remove the } near the while and put it somewhere else and you should be ok.

answered Nov 18 '11 at 18:45

Haedrian

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Syntax error on token "else" — how on earth?

7 Answers7