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Ethiopian multiplication: Difference between revisions

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Ethiopian multiplication (view source)

Revision as of 21:39, 16 August 2010

81 bytes added ,  13 years ago
→‎{{header|Erlang}}
m (Adding MUMPS example)
Line 659:
 
=={{header|Erlang}}==
<lang erlang>-module(ethiopian_multiplicationethopian).▼
{{incorrect|Erlang|Need to define and use three functions as stated in the task description}}
▲<lang erlang>-module(ethiopian_multiplication).
-export([multiply/2]).
 
halve(N) ->
multiply(Lhs, Rhs) when is_integer(Lhs) and Lhs > 0 and▼
N div 2.
 
double(N) ->
N * 2.
 
even(N) ->
(N rem 2) == 0.
 
▲multiply(LhsLHS, RhsRHS) when is_integer(Lhs) and Lhs > 0 and
is_integer(Rhs) and Rhs > 0 ->
mmultiply(LhsLHS, RhsRHS,0).
 
mmultiply(1, RhsRHS,Acc) -> Rhs;
RHS+Acc;
m(Lhs, Rhs) when 1 == (Lhs band 1) -> Rhs + m(Lhs bsr 1, Rhs bsl 1);
multiply(LHS,RHS,Acc) ->
m(Lhs, Rhs) -> m(Lhs bsr 1, Rhs bsl 1).</lang>
case even(LHS) of
true ->
multiply(halve(LHS),double(RHS),Acc);
false ->
multiply(halve(LHS),double(RHS),Acc+RHS)
end.
</lang>
 
=={{header|Factor}}==
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