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Re: in1To10

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On 8/9/2014 3:12 PM, cdalten@gmail.com wrote:
> from the url
>
> http://codingbat.com/prob/p137365
>
> The problem states: "Given a number n, return true if n is in the range 1..10, inclusive. Unless "outsideMode" is true, in which case return true if the number is less or equal to 1, or greater or equal to 10."
>
> Here is what I came up with...
>
> public class In1to10 {
> 	static boolean in1To10(int n, boolean outsideMode) {
> 		
> 		if (outsideMode == false){
> 			if (n >= 1 && n <=10) {
> 				return true;
> 			}
> 		} else if (outsideMode == true){
> 			if (n <=1 || n >=10) {
> 				return true;
> 			}
> 		}
> 		
> 		return false;
> 	}
> 	public static void main(String[] args) {
> 		System.out.println(in1To10(5, false)); //true
> 		System.out.println(in1To10(11, false)); //false
> 		System.out.println(in1To10(11, true)); //true
> 	}//end main
> }
>
>
> Now upon googling the solutions, I saw some people use
> if(outsideMode == false)
> if(outsideMode == true)
>
> instead of using if(outsideMode == false)/else(outsideMode == true).
>
> Would both catch all the cases? If not, which one would?

     Since a `boolean' can represent only the two values `true'
and `false', it follows that

     - If it isn't `true' it must be `false', and

     - If it isn't `false' it must be `true'.

Therefore, you can write

	if (outsideMode == true) {
	    // Handle the `true' case
	} else {
	    // Look, Ma: No test!
	    // Handle the `false' case
	}

... using only one `if' test.  If the test succeeds you know
`outsideMode' is `true'.  If the test fails you know `outsideMode'
is *not* `true', hence (because of the limited possibilities for
a `boolean') it must be `false'.  Alternatively, you could write

	if (outsideMode == false) {
	    // Handle the `false' case
	} else {
	    // Look, Ma: No test!
	    // Handle the `true' case
	}

... by the same reasoning: If it's not `false', it must be `true'.

     A few additional hints:

     - It's seldom if ever worth while to compare a boolean value
       to a boolean constant.  Instead of `if (outsideMode == true)'
       just write `if (outsideMode)'.  Or, if you want to be perverse,
       write `if (outsideMode == true == true == true)' ...

     - Writing `if (something) return true; else return false;' is
       kind of silly, since `return something;' does the same thing.
       Similarly, `if (something) return false; else return true;'
       can be written as `return !something;'.

-- 
esosman@comcast-dot-net.invalid

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in1To10 cdalten@gmail.com - 2014-08-09 12:12 -0700
  Re: in1To10 Jeff Higgins <jeff@invalid.invalid> - 2014-08-09 15:58 -0400
  Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-09 16:13 -0400
  Re: in1To10 Marcel Mueller <news.5.maazl@spamgourmet.org> - 2014-08-09 22:56 +0200
    Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-09 17:02 -0400
      Re: in1To10 Marcel Mueller <news.5.maazl@spamgourmet.org> - 2014-08-09 23:43 +0200
        Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-09 19:49 -0400
        Re: in1To10 Torsten Kirschner <torsten@kirschner.no> - 2014-08-10 16:59 +0200
          Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-10 11:33 -0400
            Re: in1To10 Torsten Kirschner <torsten@kirschner.no> - 2014-08-11 22:23 +0200
            Re: in1To10 Gene Wirchenko <genew@telus.net> - 2014-08-12 11:10 -0700
              Re: in1To10 Arne Vajhøj <arne@vajhoej.dk> - 2014-08-19 16:54 -0400
                Re: in1To10 Gene Wirchenko <genew@telus.net> - 2014-08-20 10:36 -0700
            Re: in1To10 Arne Vajhøj <arne@vajhoej.dk> - 2014-08-19 16:53 -0400
  Re: in1To10 cdalten@gmail.com - 2014-08-09 18:35 -0700
    Re: in1To10 Jeff Higgins <jeff@invalid.invalid> - 2014-08-09 22:13 -0400
    Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-09 22:23 -0400
    Re: in1To10 Jeff Higgins <jeff@invalid.invalid> - 2014-08-10 12:07 -0400
  Re: in1To10 Mike Amling <mamling@chaff.us> - 2014-08-10 00:29 -0500
  Re: in1To10 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2014-08-10 13:53 +0100
    Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-10 09:48 -0400
      Re: in1To10 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2014-08-10 15:01 +0100
        Re: in1To10 Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-10 10:32 -0400
          Re: in1To10 "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2014-08-10 15:53 +0100
  Re: in1To10 lipska the kat <lipskathekat@example.com> - 2014-08-10 14:07 +0100
  Re: in1To10, a simple test plan lipska the kat <lipskathekat@example.com> - 2014-08-10 16:43 +0100
    Re: in1To10, a simple test plan Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-08-10 12:01 -0400
      Re: in1To10, a simple test plan lipska the kat <lipskathekat@example.com> - 2014-08-10 17:41 +0100
      Re: in1To10, a simple test plan Arne Vajhøj <arne@vajhoej.dk> - 2014-08-19 16:57 -0400
  Re: in1To10 Roedy Green <see_website@mindprod.com.invalid> - 2014-08-12 02:59 -0700

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