You'll be glad to know! [modified]

[Peter_in_2780]

How about

for(...)
{
avar = calculation()
if(avar != someValue)
{
avar2 = someOtherCalculation();
if(avar2 != someValue2)
continue;
}
localVar.UpdateNicely();
}

The point is basically that

if (something)
goto somewhere
more_stuff;
somewhere:

is equivalent to

if (!something)
more_stuff;

and you've just got two of them nested. Cheers from one who thinks coding standards are generally a good thing but do not represent ultimate authority. Peter

Software rusts. Simon Stephenson, ca 1994.

[Super Lloyd]

well, I wanted to use some simple pseudo code, but the statement "var1 = calculation()" is really a multi inner variable multiline statement with a more complex statement. I guess I can replace it with a private static variable with heaps of ref variable just or the sake of writing such statement as you sugest, but I won't!

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[AspDotNetDev]

No excuse!

for(...)
{
if(calc() == v || calc2() == v2)
{
localVar.UpdateNicely();
}
}

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[AspDotNetDev]

Dang, you beat me.

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[Super Lloyd]

Indeed that will do! :thumbsup: :) However.... I do prefer goto to multiple nested statement! ;P

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[Luc Pattyn]

the advantage of a keyboard with a very short cable. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

[Dalek Dave]

It's neater.

------------------------------------ I will never again mention that I was the poster of the One Millionth Lounge Post, nor that it was complete drivel. Dalek Dave CCC League Table Link CCC Link[^]

[Super Lloyd]

there is the matter of avoiding goto, but this is no big deal, the real challenge is to do it in aesthetic and readable way! Well, I guess it's a subjective matter... But just to give you better chance, here is the real code. I think goto is the most elegant / beautiful solution. I invite you to show me the beauty of avoiding goto! (Although.. being a subjective thing... well....) Here we go:

for (int i = max; i >= min; i--)
{
var v1 = new Vector2D(points[i > 0 ? i - 1 : points.Count - 1], points[i]);
var v2 = new Vector2D(points[i], points[i < points.Count - 1 ? i + 1 : 0]);
if (v1.SquareNorm <= MINL || v2.SquareNorm <= MINL)
goto RemovePoint;
v1 = v1.Normalize(); // divide by zero if test above fail
v2 = v2.Normalize();
var z = v1 ^ v2;
if (Math.Abs(z) <= minsin && v1 * v2 < 0)
goto RemovePoint;
continue;
RemovePoint: ;
points.RemoveAt(i);
if (points.Count < 3)
return null;
}

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

modified on Thursday, September 9, 2010 8:31 PM

[AspDotNetDev]

The only acceptable place I've found for a goto is within a switch block. After all, the "labels" are already defined.

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[PIEBALDconsult]

Until I did some refactoring today I had a method with three return statements! :omg: (They were to avoid a goto to abort a nested loop.)

[Luc Pattyn]

Well, the complexity of avar1 = someCalculation(); isn't relevant, you can do it upfront anyway. The complexity of avar2 = someOtherCalculation(); is what matters. If it can't be put in the middle of the if clause, I'd use a boolean flag, like so:

for (...) {
bool updateWanted=false;
if (calculation()==someValue) updateWanted=true;
else if (someOtherCalculation()==someValue2) updateWanted=true;
if (updateWanted) localVar.UpdateNicely();
}

and now you can easily expand line 4 (and 3) as required. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

modified on Thursday, September 9, 2010 8:52 PM

[AspDotNetDev]

PIEBALDconsult wrote:

avoid a goto to abort a nested loop

I usually set some bool, break, then conditionally break depending on the value in the bool. Slows things down a bit, so a goto might be more acceptable in this case if speed is of significant importance and the inner loop does not have many iterations.

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[Luc Pattyn]

it's like writing poetry, just keep scrapping the redundant bits until you start to like the result. Except you have to adhere to the original intentions... :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

[Super Lloyd]

see the code below! it can't be done upfront, as the first if will avoid as divide by zero in the second if! just for your benefit I post the code below again! Anyway, yes it can be done, but I found my way more readable... I guess it's too subjective for debate.. but I invite you to show me the new version:

for (int i = max; i >= min; i--)
{
var v1 = new Vector2D(points[i > 0 ? i - 1 : points.Count - 1], points[i]);
var v2 = new Vector2D(points[i], points[i < points.Count - 1 ? i + 1 : 0]);
if (v1.SquareNorm <= MINL || v2.SquareNorm <= MINL)
goto RemovePoint;
v1 = v1.Normalize(); // divide by zero if square norm is 0 (test above)
v2 = v2.Normalize();
var z = v1 ^ v2;
if (Math.Abs(z) <= minsin && v1 * v2 < 0)
goto RemovePoint;
continue;
RemovePoint: ;
points.RemoveAt(i);
if (points.Count < 3)
return null;
}

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[Super Lloyd]

Thanks! Glad someone agree! I think I was looking for a beating... but I have a hard time handling it! :laugh:

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[Peter_in_2780]

Two comments. 1. Loops are only nested too deep when you need to indent each level by less than [insert favourite small number here, mine's 4] spaces to fit it on the screen. ;P The construct

if (!test)
goto next;
do_stuff;
next:

is actually what a compiler* will emit if you feed it

if (test)
do_stuff;

Ironic, huh? But maybe that's why we deal in the input to compilers and leave their output unseen. * for a typical target instruction set

Software rusts. Simon Stephenson, ca 1994.

[Super Lloyd]

Ho my god! That Is Bad! :laugh:

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[AspDotNetDev]

If you really don't want to put some of that logic into functions, this is one way to go:

for(...)
{
bool doRemove = false;
var v1 = a();
var v2 = b();
if(v1.a() || v2.a())
{
doRemove = true;
}
else
{
v1 = c();
v2 = d();
var z = e();
if(e(z, v1, v2))
{
doRemove = true;
}
}
if(doRemove)
{
RemovePoint();
}
}

I put in some placeholders where I didn't feel like typing.

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[Super Lloyd]

mmh... so you mean your way is better because it will compile to my way?!? ;P anyway, at this stage it's a matter of taste, your solution is elegant too! but too many bracket confuses me and the compiler in my brain! (as opposed to the one on the hard drive ;) )

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.

[Luc Pattyn]

I already gave my preferred structure here[^], and I think we've had enough code in the Lounge for this week... :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.