Ethiopian multiplication: Difference between revisions

<!-- {{does not work with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release 1.8.8d.fc9.i386 - missing printf and FORMAT}} -->

PROC doublit = (REF INT x)VOID: x := ABS(BIN x SHL 1);

PROC iseven = (#CONST# INT x)BOOL: NOT ODD x;

(

printf(($g(0)l$, ethiopian(17, 34, TRUE)))

Output:

<pre>

Here is such an implementation without tutor, since there is no mechanism in C++ to output

messages during program compilation.

struct Half

{

std::cout << EthiopianMultiplication<17, 54>::Result << std::endl;

return 0;

=={{header|C sharp|C#}}==

{

EthopianMultiplication(17, 34);

Version with as a function of functions:

<cfargument name="number" type="numeric" required="true">

<cfset answer = number * 2>

Version with display pizza:

<cfset Number_B = 34>

<cfset Result = 0>

...equals #Result#

Sample output:

=={{header|Clojure}}==

(bit-shift-right n 1))

(if (even a)

(recur (halve a) (twice b) r)

=={{header|Common Lisp}}==

=={{header|D}}==

int dub(int num) { return num << 1; }

int halve(int num) { return num >> 1; }

writefln("17 ethiopian 34 is %d", ethiopian(17, 34));

return 0;

=={{header|E}}==

=={{header|FALSE}}==

[2*]d:

[1&]o:

'''Solution''':

'''Example''':

Note: this could be implemented more concisely as <tt>#.@(*#:)</tt>, which abides by the letter of the task, but [http://www.jsoftware.com/pipermail/programming/2009-July/015507.html evades its spirit].

}</lang>

An optimised variant using the three helper functions from the other example.

}

}

}

}

== {{header|JavaScript}} ==

halve : function ( n ){ return Math.floor(n/2); },

}

=={{header|Logo}}==

output ashift :x 1

end

[output eproduct halve :x double :y] ~

[output :y + eproduct halve :x double :y]

=={{header|Metafont}}==

=={{header|PL/SQL}}==

This code was taken from the ADA example above - very minor differences.

function multiply

dbms_output.put_line(ethiopian.multiply(17, 34));

end;

Everything encapsulated in one function.

-- works at least on PostgreSQL 8.3, should work in older versions as well

DECLARE

RETURN sum;

END;

NOTICE: 8, 68 STRIKE

NOTICE: 4, 136 STRIKE

--------------------------

578

=={{header|PowerShell}}==

param ([int]$value)

return [bool]($value % 2 -eq 0)

}

=={{header|Python}}==

def halve(x):

multiplicand = double(multiplicand)

if tutor: print()

Sample output

Without the tutorial code, and taking advantage of Python's lambda:

double = lambda x: x*2

even = lambda x : not x % 2

multiplicand = double(multiplicand)

=={{header|R}}==

=={{header|SNUSP}}==

| | /-\ /recurse\ #/?\ zero

$>,@/>,@/?\<=zero=!\?/<=print==!\@\>?!\@/<@\.!\-/

\>+<-/ | \=<<<!/====?\=\ | double

! # | \<++>-/ | |

This is possibly the smallest multiply routine so far discovered for SNUSP.

functions are normally imported from the nat library but defined here explicitly for

the sake of completeness.

double = ~&iNiCB

The functions above are defined in terms of bit manipulations exploiting the concrete representations

of natural numbers. The remaining code treats natural numbers instead as abstract types by way of the library API, and uses the operators for distribution (*-), triangular iteration (|\),

and filtering (*~) among others.

test program:

output:

<pre>