Groups > comp.lang.java.programmer > #16924

Re: initialize an array of booleans

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From	"Eric Sosman" <eric.sosman@1:261/38.remove-s5i-this>
Subject	Re: initialize an array of booleans
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  To: bob smith
From: Eric Sosman <esosman@ieee-dot-org.invalid>

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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Thread

initialize an array of booleans "bob smith" <bob.smith@1:261/38.remove-s5i-this> - 2012-08-01 18:09 +0000
  Re: initialize an array of booleans "Eric Sosman" <eric.sosman@1:261/38.remove-s5i-this> - 2012-08-01 18:09 +0000
  Re: initialize an array of booleans "Lew" <lew@1:261/38.remove-s5i-this> - 2012-08-01 18:09 +0000
  Re: initialize an array of booleans "Roedy Green" <roedy.green@1:261/38.remove-s5i-this> - 2012-08-01 18:09 +0000

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