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Groups > comp.lang.java.programmer > #16894

Re: initialize an array of booleans

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On 7/31/2012 3:58 PM, bob smith wrote:
> Is there any easy way to initialize an array of booleans like this?
>
> boolean b[] = new boolean(false)[100];

     Sure: `boolean b[] = new boolean[100];' will do it, although
`boolean[] b = new boolean[100];' is usually considered better style.

     ... but that's just because a freshly-created boolean is `false'
until and unless it's given another value, just as a freshly-created
int is zero.  To initialize with a lot of `true's you could write

	boolean[] b = new boolean[]{true,true,true, /*etc.*/};

... but that would be tedious, error-prone, and inefficient (you'd
be dismayed at the number of byte code instructions generated). It'd
be better to use a loop, either in open code:

	boolean[] b = new boolean[100];
	for (int i = 0; i < b.length; ++i)
	    b[i] = true;

... or with the prepackaged array-filling method:

	boolean[] b = new boolean[100];
	java.util.Arrays.fill(b, true);

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

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initialize an array of booleans bob smith <bob@coolfone.comze.com> - 2012-07-31 12:58 -0700
  Re: initialize an array of booleans Lew <lewbloch@gmail.com> - 2012-07-31 13:08 -0700
  Re: initialize an array of booleans Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-07-31 16:12 -0400
  Re: initialize an array of booleans Roedy Green <see_website@mindprod.com.invalid> - 2012-07-31 14:08 -0700

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