Talk:Casting out nines: Difference between revisions
Go solution updated
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::::OK, maybe you have misunderstood what I am trying to convey. Following Dr. Math at http://mathforum.org/library/drmath/view/55926.html describing casting out nines to the phrase "(You wouldn't normally get the same check digit for the result of the sum and the products; I just picked a weird example.)" I see that every Kaprekar is a "weird example". Using Dr. Maths "quick explanation of how to do it, without the big words" would be as slow as the String C++ Kaprekar solution. So we turn to http://mathworld.wolfram.com/CastingOutNines.html. What is said there is true for bases other than 10, therefore it is possible to develop a fast test. --[[User:Nigel Galloway|Nigel Galloway]] 12:47, 27 June 2012 (UTC)
:::(Comments moved from task page following Go solution.) I'm not seeing the connection. —[[User:Sonia]]
::::If you replace the line <code>if k%(base-1) == (k*k)%(base-1) {</code> with something like <code>if co9Peterson(k) == co9Peterson(k*k) {</code> in the C++ translation would it not solve the task? Obviously as written you would have to change k and k*k to strings and it would only work base10, but I think you have demonstrated the connection.--[[User:Nigel Galloway|Nigel Galloway]] 15:15, 28 June 2012 (UTC)
::: Done. Posted now are my two Go solutions combined, generalized to other bases, and then modified to demonstrate what the task seems to be asking for. I do think that people will protest that my casting out nines code is superfluous, and I will then repeat that the task should not be called casting out nines if nothing in the task is casting out nines. —[[User:Sonia|Sonia]] 19:20, 28 June 2012 (UTC)
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