Programming Forums > Application Development > Java

Eric the Red · May 21st, 2006, 6:28 PM

Does anyone know how to break out of a double loop?

I understand that by using "break;" you can jump out of a loop. But what happens when i'm running through a 2-d array and i want to break out of a double loop? Is there any simple way like "break, break;" or "break 2x" LOL?
I could assign a boolean variable "true" then test whether it is true in the outer loop.

example:

(Toggle Plain Text)

                            for (y= 0; y < 10;y++)
                            {
                              for (x = 0; x < 10; x++)
                              {
                                 if (arrayTwoDimension[x][y].getState = true)
                                 {
                                    blnBreak = true;
                                    break;
                                  }
                              }
                              if (blnBreak = true)  // tedious
                                  break;
                            }

Note the test in the 'y loop' (blnBreak = true).

Anyone know a quick fix for this problem? What should I be doing in this situation?

andro · May 21st, 2006, 6:35 PM

(Toggle Plain Text)

	myBreakLabel:
		for (int x = 0; x < 10; x++)
		{
			for (int y = 0; y < 10; y++)
			{
				if (array[x][y].getState == true)
				{
					break myBreakLabel;
				}
			}
		}

Jimbo · May 21st, 2006, 6:37 PM

you could use the idea you proposed, or you might consider using a label. This is pretty much the goto of Java, so some people might not like it. There's a blurb on labels here. Remember that the label comes before the outer loop, but will break you out of it.

[edit:] doggone you, andro... :p

Eric the Red · May 21st, 2006, 6:40 PM

Well.. What would an expert java programmer do in this situation?

Jimbo · May 21st, 2006, 6:47 PM

I can't say for sure what an "expert" would do, but I'd use the label

ReggaetonKing · May 21st, 2006, 6:59 PM

Sounds like the best solution. I forgot about labels myself.

Mjordan2nd · May 21st, 2006, 7:07 PM

I don't know what the best way to do it, or what the expert way to do it would be, but normally I just use a boolean value like you proposed.

Booooze · May 21st, 2006, 9:33 PM

I would use a boolean value. Never used a label before, but looks just as effective. If I knew about labels, I would probably use em'. Don't do much java anymore :p

DaWei · May 21st, 2006, 10:32 PM

I would go either way. When it comes to goto, as in C, you can put the goto label in strange, non-related out-of-the-way places and really do some spaghetti code screwups. In the situation you're looking at, the break terminates the labeled construct, rather than branching TO the label. I see nothing wrong with it. Of course, I'm not a high-priest looking for acolytes to kiss my ring. I'm an acolyte looking for a high-priest to kiss my butt.

andro · May 21st, 2006, 10:47 PM

A third solution:

(Toggle Plain Text)

x=10;
y=10;

May 21st, 2006, 6:28 PM	#1
Eric the Red Hobbyist Programmer Join Date: Feb 2006 Posts: 214 Rep Power: 0	Break statement Does anyone know how to break out of a double loop? I understand that by using "break;" you can jump out of a loop. But what happens when i'm running through a 2-d array and i want to break out of a double loop? Is there any simple way like "break, break;" or "break 2x" LOL? I could assign a boolean variable "true" then test whether it is true in the outer loop. example: (Toggle Plain Text) for (y= 0; y < 10;y++) { for (x = 0; x < 10; x++) { if (arrayTwoDimension[x][y].getState = true) { blnBreak = true; break; } } if (blnBreak = true) // tedious break; } for (y= 0; y < 10;y++) { for (x = 0; x < 10; x++) { if (arrayTwoDimension[x][y].getState = true) { blnBreak = true; break; } } if (blnBreak = true) // tedious break; } Note the test in the 'y loop' (blnBreak = true). Anyone know a quick fix for this problem? What should I be doing in this situation? __________________ Death smiles at us all. All a man can do is smile back.

May 21st, 2006, 6:35 PM	#2
andro Professional Programmer Join Date: Oct 2005 Location: California Posts: 311 Rep Power: 3	(Toggle Plain Text) myBreakLabel: for (int x = 0; x < 10; x++) { for (int y = 0; y < 10; y++) { if (array[x][y].getState == true) { break myBreakLabel; } } } myBreakLabel: for (int x = 0; x < 10; x++) { for (int y = 0; y < 10; y++) { if (array[x][y].getState == true) { break myBreakLabel; } } }

May 21st, 2006, 6:40 PM	#4
Eric the Red Hobbyist Programmer Join Date: Feb 2006 Posts: 214 Rep Power: 0	Well.. What would an expert java programmer do in this situation? __________________ Death smiles at us all. All a man can do is smile back.

May 21st, 2006, 6:59 PM	#6
ReggaetonKing Sexy Programmer Join Date: Nov 2005 Location: New Jersey Posts: 891 Rep Power: 3	Sounds like the best solution. I forgot about labels myself. __________________ I would love to change the world, but they won't give me the source code!

May 21st, 2006, 7:07 PM	#7
Mjordan2nd The Supreme Ruler Join Date: May 2004 Location: Houston Posts: 1,476 Rep Power: 6	I don't know what the best way to do it, or what the expert way to do it would be, but normally I just use a boolean value like you proposed. __________________ "Every gun that is made, every warship launched, every rocket signifies, in the final sense, a theft from those who hunger and are not fed, from those who are cold and are not clothed. The world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children." - Dwight D. Eisenhower

May 21st, 2006, 6:37 PM	#3
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 763 Rep Power: 3	you could use the idea you proposed, or you might consider using a label. This is pretty much the goto of Java, so some people might not like it. There's a blurb on labels here. Remember that the label comes before the outer loop, but will break you out of it. [edit:] doggone you, andro... :p

May 21st, 2006, 6:47 PM	#5
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 763 Rep Power: 3	I can't say for sure what an "expert" would do, but I'd use the label

May 21st, 2006, 9:33 PM	#8
Booooze Expert Programmer Join Date: Mar 2006 Location: Igloo Posts: 710 Rep Power: 3	I would use a boolean value. Never used a label before, but looks just as effective. If I knew about labels, I would probably use em'. Don't do much java anymore :p

May 21st, 2006, 10:32 PM	#9
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	I would go either way. When it comes to goto, as in C, you can put the goto label in strange, non-related out-of-the-way places and really do some spaghetti code screwups. In the situation you're looking at, the break terminates the labeled construct, rather than branching TO the label. I see nothing wrong with it. Of course, I'm not a high-priest looking for acolytes to kiss my ring. I'm an acolyte looking for a high-priest to kiss my butt. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

May 21st, 2006, 10:47 PM	#10
andro Professional Programmer Join Date: Oct 2005 Location: California Posts: 311 Rep Power: 3	A third solution: (Toggle Plain Text) x=10; y=10; x=10; y=10;

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Programming Forums > Application Development > Java

Break statement