The 20line or less weekly contest!

[Zasalamel]

Yeah mirhagk! i didn't think you would post it...

[mirhagk]

didn't think I'd post what?? the mona lisa thing, or the code used to make it??

[Superskull85]

I was wondering how small I could make my base conversion program, and still make it usable (not entirely "the best").

Any base 2-36 to decimal (10):

Turing:

var Num : string function IsValid (Num : string) : boolean     if length (Num) not= 0 then         result ((ord (Num (1)) >= 48 and ord (Num (1)) <= 57) or (ord (Str.Upper (Num (1))) >= 65 and ord (Str.Upper (Num (1))) <= 90)) and IsValid (Num (2 .. *))     end if     result true end IsValid function ConvertBaseDec (Num : string, Base : int) : int     if length (Num) = 0 or not IsValid (Num) then         result 0     end if     if ord (Num (1)) >= 48 and ord (Num (1)) <= 57 then         result strint (Num (1)) * (Base ** (length (Num) - 1)) + ConvertBaseDec (Num (2 .. *), Base)     else         result (ord (Num (1)) - 55) * (Base ** (length (Num) - 1)) + ConvertBaseDec (Num (2 .. *), Base)     end if end ConvertBaseDec put "Input a base 2-36 number, and the base (number:base): " .. get Num put ConvertBaseDec (Num (1 .. index (Num, ":") - 1), strint (Num (index (Num, ":") + 1 .. *)))

Decimal (10) to any base 2-36:

Turing:

var Num : string function SetValue (Num : int) : string     if Num >= 10 then         result chr (Num - 10 + 65)     else         result intstr (Num)     end if end SetValue function ConvertDecBase (Num, Base : int) : string     if Num = 0 then         result ""     end if     result ConvertDecBase (Num div Base, Base) + SetValue (Num mod Base) end ConvertDecBase put "Input a decimal number, and a base (number:base): " .. get Num if strintok (Num (1 .. index (Num, ":") - 1)) then     put ConvertDecBase (strint (Num (1 .. index (Num, ":") - 1)), strint (Num (index (Num, ":") + 1 .. *))) end if

I am pretty sure the algorithms will convert any number given. If not let me know.

I know this is not the best algorithm that could be designed, but it gave me a challenge and made me look at the problem in a whole different way.

[Tony]

Superskull85 @ Wed Dec 09, 2009 12:02 am wrote:

I know this is not the best algorithm that could be designed

Wait, is the algorithm "use strint", or are you talking about validation/parsing-input?

[Superskull85]

Using strint would accomplish the same thing but would not allow you to express numbers in other bases as you would be limited to the bases 2 through 36.

Using my method you could convert a base one number, such as "11111" into decimal (would be five) if you wanted to (you cannot convert decimal to base one using my method).

Also by adding/changing a couple of lines you could represent all the bases between 2 and 62 using all numerical characters (0-9), and all upper case (A-Z) and lower case (a-z) letters.

Any base 1-36 to decimal (10):

Turing:

var Num : string function IsValid (Num : string) : boolean     if length (Num) not= 0 then         result ((ord (Num (1)) >= 48 and ord (Num (1)) <= 57) or                 (ord (Str.Upper (Num (1))) >= 65 and ord (Str.Upper (Num (1))) <= 90) or                 (ord (Str.Upper (Num (1))) >= 97 and ord (Str.Upper (Num (1))) <= 122))                 and IsValid (Num (2 .. *))     end if     result true end IsValid function ConvertBaseDec (Num : string, Base : int) : int     if length (Num) = 0 or not IsValid (Num) then         result 0     end if     if ord (Num (1)) >= 48 and ord (Num (1)) <= 57 then         result strint (Num (1)) * (Base ** (length (Num) - 1)) + ConvertBaseDec (Num (2 .. *), Base)     elsif ord (Num (1)) >= 65 and ord (Num (1)) <= 90 then         result (ord (Num (1)) - 55) * (Base ** (length (Num) - 1)) + ConvertBaseDec (Num (2 .. *), Base)     else         result (ord (Num (1)) - 61) * (Base ** (length (Num) - 1)) + ConvertBaseDec (Num (2 .. *), Base)            end if end ConvertBaseDec put "Input a base 1-62 number, and the base (number:base): " .. get Num put ConvertBaseDec (Num (1 .. index (Num, ":") - 1), strint (Num (index (Num, ":") + 1 .. *)))

Any decimal (10) to base 2-62:

Turing:

var Num : string function SetValue (Num : int) : string     if Num >= 36 then         result chr (Num - 36 + 97)     elsif Num >= 10 then         result chr (Num - 10 + 65)     else         result intstr (Num)     end if end SetValue function ConvertDecBase (Num, Base : int) : string     if Num = 0 then         result ""     end if     result ConvertDecBase (Num div Base, Base) + SetValue (Num mod Base) end ConvertDecBase put "Input a decimal number, and a base (2-62) (number:base): " .. get Num if strintok (Num (1 .. index (Num, ":") - 1)) then     put ConvertDecBase (strint (Num (1 .. index (Num, ":") - 1)), strint (Num (index (Num, ":") + 1 .. *))) end if

You cannot do this with strint.

So to be specific I should of said, "I was wondering how small I could make my base conversion program, without using strint and still make it usable (not entirely "the best")." instead in my previous post.

[Tony]

Oh, I see what's going on now. At first I just saw the use of strint, but now your description also explains how this works beyond the limitations. Nice.

[Magix]

Here I am with another submission...a prime number finder... with Turing! You enter a low number and a high number, and the program can list out for you all the prime numbers between them, and in the end, it outputs the total number of prime numbers. Only problem is that, because of my noob coding and Turing's un-flexibility, it runs very slowly if the gap between the numbers you enter is too big. If you enter 1 and 10,000, it runs just fine, but enter 1 and 100,000, and the thing gets slower. It still works though.

code:

var iNum1, iNum2, iDiv, iPrm : int iPrm := 0                                   %Initial value put "Starting number: " ..                  %Caption get iNum1                                   %Get lower number put "Ending number: " ..                    %Caption get iNum2                                   %Get higher number put "List of prime numbers between ", iNum1, " and ", iNum2, "..." for count : iNum1 .. iNum2                  %Starts for loop to execute     iDiv := 0                               %Set number of factors to 0     for fDivider : 1 .. iNum2               %Starts divident finder         if count mod fDivider = 0 then      %If remainder=0, then             iDiv := iDiv + 1                %Add 1 to total number of factors         end if                              %End if     end for                                 %End for loop     if iDiv = 2 then                        %If it has no factors...         iPrm := iPrm + 1                    %Add 1 to number of prime numbers         put count                           %Output number     end if                                  %End if end for put "There are ", iPrm, " prime numbers between ", iNum1, " and ", iNum2, "."

This version is super-compressed to fit into 20 lines. If you want to see the full version, click here.

[mirhagk]

Hey just a little tip
this section:

Turing:

for fDivider : 1 .. iNum2     if count mod fDivider = 0 then         iDiv := iDiv + 1     end if end for

you don't need to check if it's divisible by one right? so start it at 2 (will increase speed a little)
also you already know it's divisble by itself and not divisible by numbers greater than itself. So you only need to check for numbers smaller than itself (count-1)
heres what that section should look like (also remember to change the if statement checking how many factors it has, it should have 0 with the new improvements to the code)

Turing:

for fDivider : 2 .. count-1                      if count mod fDivider = 0 then                  iDiv := iDiv + 1                        end if                                  end for

[Tony]

mirhagk @ Sun Dec 13, 2009 9:58 am wrote:

So you only need to check for numbers smaller than itself (count-1)

One might notice that there is a lot more numbers one does not need to check to see if a number is prime or not.

Do we need to check count-2? -3? How many can we take off, and still be certain in the true/false answer for number being prime?

[DemonWasp]

...and do we really need to know how many factors the number has? Isn't it enough to know that it has factors other than 1 and itself?

[mirhagk]

wouldnt it be more effecient to keep an array of all the numbers set to true then set them to false if you find a number it's divisible by.

then when your checking the number you can check against only if the number is true (so it only checks against prime numbers).

[ecookman]

some really cool stuff here, I am just for fun going to see if I can make anything like these. Wait, isn't it possible to code everything in one line?

[mirhagk]

with a ; but otherwise no. (well maybe some programs but not most useful programs)

[Tony]

mirhagk @ Sun Dec 13, 2009 11:37 pm wrote:

wouldnt it be more effecient to keep an array of all the numbers...

If you want to check a range of numbers, yes, you can use a sieve (and it would be ridiculously better); but it's not really applicable if we are checking just one number (well, it could be used in a way that we find all the primes up the current number we are checking, but that's extra work).

[mirhagk]

well the program i have in mind would cancel out checking numbers if they have been declared by the program to be non-prime