How does the break statement work?

[Cogito]

For the first time, I'm attempting to write a small Javascript program
using one on the online reference sites. I need some confirmation as
to the behaviour of the break statement.

In the following code:

for ( row = 0 ; row <= 7 ; row++ ) A <----
{
for ( col = 0 ; col <=7 ; col++ ) B <----
{
if ( check ( row, col ) == "pass" )
break ;
}
}
}

Where will control pass to once the break statement is executed?
Will it continue with the first 'for' statement (A) or the second (B)?

Also my 'check' function needs to pass an indication as to it's
success or failure. It does it by:

return ( "pass" ) ;

Am I doing it correctly?

Any links to useful reference sites would be welcomed.

[Dr J R Stockton]

In comp.lang.javas cript message <67vuv2tsvj2vr7 hb4jf0up90b5cla a18gr@4ax.
com>, Tue, 20 Mar 2007 06:33:47, Cogito <no****@nospam. nospamposted:

>For the first time, I'm attempting to write a small Javascript program
using one on the online reference sites. I need some confirmation as
to the behaviour of the break statement.

In the following code:

for ( row = 0 ; row <= 7 ; row++ ) A <----
{
for ( col = 0 ; col <=7 ; col++ ) B <----
{
if ( check ( row, col ) == "pass" )
break ;
}
}
}

Where will control pass to once the break statement is executed?
Will it continue with the first 'for' statement (A) or the second (B)?

Also my 'check' function needs to pass an indication as to it's
success or failure. It does it by:

return ( "pass" ) ;

Am I doing it correctly?

Any links to useful reference sites would be welcomed.

The following structures should do what you seem to need.

function check(a, b) { return a*b != 21 } // Test dummy

function owZat() { var row, col
for ( row = 0 ; row <= 7 ; row++ )
for ( col = 0 ; col <= 7 ; col++ )
if ( ! check ( row, col ) ) return false
return true }

// or

OK = true
DOWN:
for ( row = 0 ; row <= 7 ; row++ )
for ( col = 0 ; col <= 7 ; col++ )
if ( ! check ( row, col ) ) { OK = false ; break DOWN }
It's a good idea to read the newsgroup c.l.j and its FAQ. See below.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6
news:comp.lang. javascript FAQ <URL:http://www.jibbering.c om/faq/index.html>.
<URL:http://www.merlyn.demo n.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[Evertjan.]

Richard Cornford wrote on 20 mrt 2007 in comp.lang.javas cript:

A ladled break statement would be as effective.

function checkTable(){
var passed = true;
outerLoop: for(var row = 0;row < 8;++row){
for(var col = 0;col < 8;++col){
if(!(passed = check(row, col))){

==

break outerLoop;
}
}
}
return passed;
}

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Richard Cornford]

"Evertjan." wrote:

Richard Cornford wrote on 20 mrt 2007 in comp.lang.javas cript:

>A ladled break statement would be as effective.

function checkTable(){
var passed = true;
outerLoop: for(var row = 0;row < 8;++row){
for(var col = 0;col < 8;++col){
if(!(passed = check(row, col))){

==

<snip>

Look again.

Richard.

[Cogito]

Many thanks for all your replies and comments. They were all of great
help. I have implemented some of them but unfortunately my program now
goes into a state of deep thoughts and produces a beautiful white
screen.

As they say, back to the drawing board. I think that my two nested
'for' loops will have to go and be replaced by a single 'while' loop.
It seems that since I modify the values of 'col' and 'row' in the loop
itself, I somehow end up in an endless loop.

One more question before I embark on reshaping the code: Can you have
multiple conditions to control the termination of a loop ('for' or '
while') or is it limited just one condition? Searching through some of
the sites I could not find an example with more than one test.

[Dr J R Stockton]

In comp.lang.javas cript message <1b2203dtih5ts0 l99m94fin52ra92 gskqg@4ax.
com>, Wed, 21 Mar 2007 10:44:40, Cogito <no****@nospam. nospamposted:

>
As they say, back to the drawing board. I think that my two nested
'for' loops will have to go and be replaced by a single 'while' loop.
It seems that since I modify the values of 'col' and 'row' in the loop
itself, I somehow end up in an endless loop.

One can do that in javascript, but it is generally better not to alter
the control values for FOR loops in the body of the loop.

>One more question before I embark on reshaping the code: Can you have
multiple conditions to control the termination of a loop ('for' or '
while') or is it limited just one condition? Searching through some of
the sites I could not find an example with more than one test.

There can only be a single Boolean condition; but the calculation of
that can be as complex as you like.

This peculiar sample code, if executed in alternate 5-second periods on
a Wednesday, will whizz-count in status until the end of the period, and
otherwise does nothing :-
for ( ; D = new Date(), D.getSeconds()% 10<5 && D.getDay()==3 ; )
{ window.status++ }

A break statement will also terminate a loop; and the condition for
its execution is a Boolean value, calculated however you wish; so the
contents of if( ) can be a complex Boolean expression.

It's a good idea to read the newsgroup c.l.j and its FAQ. See below.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6
news:comp.lang. javascript FAQ <URL:http://www.jibbering.c om/faq/index.html>.
<URL:http://www.merlyn.demo n.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[Cogito]

I have one more very basic question. How do you check for typing
errors?
Say, I type my program using Notepad and I have a variable called
'area'. Some fifty lines of code later I make reference to this
variable and due to a typo I enter 'arae'. How will I ever discover
the mistake?

[RobG]

On Mar 22, 4:24 pm, Cogito <nos...@nospam. nospamwrote:

I have one more very basic question. How do you check for typing
errors?
Say, I type my program using Notepad and I have a variable called
'area'. Some fifty lines of code later I make reference to this
variable and due to a typo I enter 'arae'. How will I ever discover
the mistake?

Your program probably won't work the way you expect. Frequent and
thorough testing is always required.

--
Rob

[Cogito]

On 22 Mar 2007 01:22:30 -0700, "RobG" <rg***@iinet.ne t.auwrote:

>On Mar 22, 4:24 pm, Cogito <nos...@nospam. nospamwrote:

>I have one more very basic question. How do you check for typing
errors?
Say, I type my program using Notepad and I have a variable called
'area'. Some fifty lines of code later I make reference to this
variable and due to a typo I enter 'arae'. How will I ever discover
the mistake?

Your program probably won't work the way you expect. Frequent and
thorough testing is always required.

I have no doubt that the program won't work but how would you detect
such an error?
In the days when I programmed mainframe computers, the process of
compiling the program would highlight such mistakes well before
program execution.

[Evertjan.]

Cogito wrote on 22 mrt 2007 in comp.lang.javas cript:

On 22 Mar 2007 01:22:30 -0700, "RobG" <rg***@iinet.ne t.auwrote:

>>On Mar 22, 4:24 pm, Cogito <nos...@nospam. nospamwrote:

>>I have one more very basic question. How do you check for typing
errors?
Say, I type my program using Notepad and I have a variable called
'area'. Some fifty lines of code later I make reference to this
variable and due to a typo I enter 'arae'. How will I ever discover
the mistake?

Your program probably won't work the way you expect. Frequent and
thorough testing is always required.

I have no doubt that the program won't work but how would you detect
such an error?
In the days when I programmed mainframe computers, the process of
compiling the program would highlight such mistakes well before
program execution.

However, in scripting that is not the case.
In scripting there is no compiling involved in the sense that the compiled
result is distributed. That is why it is called scripting.

On the other hand we noow have the concept of modular programming,
helping you in the art of debugging.

I hope you mean "area" as the name of a js variable.

for <area .. please ask a html NG.

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Cogito]

>

>I hope you mean "area" as the name of a js variable.

for <area .. please ask a html NG.

Actually I did not. It was just a word I picked at random. I was just
wondering if there is a way of detecting typos other than careful
scrutiny.