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Re: Game of life from K&R: question about switch statement

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On 11/17/2015 11:34 AM, Alla _ wrote:
> Hello!
>
> Please, take a look a the program from K&R tutorial; it has descriptive
> comments, therefore I will skip adding my ones. I would be grateful
> for the help.
>
> I am not sure I understand how the switch statement works within
> BuildNextGeneration () function. I read it as:
>
> if a value at the position array[i][j] is '*', then the program
> has to choose between 3 cases. Given each case in switch statement should
> have a certain value to which the condition is compared, I don't
> understand what 2 or 3 represent:

     The three cases are "two neighbors," "three neighbors," and "other."
This suggests a switch statement with the general outline:

	switch (neighbors) {
	    case 2:
	        // handle "two neighbor" case
	        break;
	    case 3:
	        // handle "three neighbors" case
	        break;
	    default:
	        // handle "other" case
	        break;
	}

     It turns out that the handling is the same for the two- and three-
neighbors cases, so we can combine those two in the switch:

	switch (neighbors) {
	    case 2:
	    case 3:
	        // handle "two neighbors" or "three neighbors"
	        break;
	    default:
	        // handle "other" case
	        break;
	}

     This could have been written in other ways, like

	if (neighbors == 2 || neighbors == 3) {
	    // handle "two neighbors" or "three neighbors"
	} else {
	    // handle "other" case
	}

... but I'm guessing the point of the lesson is to teach you about
the switch statement.  Too bad you've not been given a more compelling
example.

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM

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Game of life from K&R: question about switch statement Alla _ <modelling.data@gmail.com> - 2015-11-17 08:34 -0800
  Re: Game of life from K&R: question about switch statement Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-17 11:46 -0500
  Re: Game of life from K&R: question about switch statement James Kuyper <jameskuyper@verizon.net> - 2015-11-17 11:56 -0500
    Re: Game of life from K&R: question about switch statement glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-17 20:19 +0000
      Re: Game of life from K&R: question about switch statement "Charles Richmond" <numerist@aquaporin4.com> - 2015-11-19 17:48 -0600
  Re: Game of life from K&R: question about switch statement Stephen Sprunk <stephen@sprunk.org> - 2015-11-17 12:27 -0600
  Re: Game of life from K&R: question about switch statement Keith Thompson <kst-u@mib.org> - 2015-11-17 15:12 -0800

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