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Ethiopian multiplication: Difference between revisions
Ada
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*[http://www.ncetm.org.uk/blogs/3064 Ethiopian multiplication]
*[http://www.bbc.co.uk/dna/h2g2/A22808126 Russian Peasant Multiplication]
=={{header|Ada}}==
<lang Ada>package Ethiopian is
function Multiply(Left, Right : Integer) return Integer;
end Ethiopian;</lang>
<lang Ada>package body Ethiopian is
function Is_Even(Item : Integer) return Boolean is
begin
return Item mod 2 = 0;
end Is_Even;
function Double(Item : Integer) return Integer is
begin
return Item * 2;
end Double;
function Half(Item : Integer) return Integer is
begin
return Item / 2;
end Half;
function Num_Doubles(Item : Integer) return Natural is
Count : Natural := 0;
Temp : Integer := Item;
begin
loop
Count := Count + 1;
Temp := Half(Temp);
exit when not Is_Even(Temp);
end loop;
return Count;
end Num_Doubles;
function Multiply(Left, Right : Integer) return Integer is
Temp : Integer := Right;
begin
for I in 1..Num_Doubles(Left) loop
Temp := Double(Temp);
end loop;
Temp := Temp + Right;
return Temp;
end Multiply;
end Ethiopian;</lang>
<lang Ada>with Ethiopian; use Ethiopian;
with Ada.Text_Io; use Ada.Text_Io;
procedure Ethiopian_Test is
First : Integer := 17;
Second : Integer := 34;
begin
Put_Line(Integer'Image(First) & " times " &
Integer'Image(Second) & " = " &
Integer'Image(Multiply(First, Second)));
end Ethiopian_Test;</lang>
=={{header|AutoHotkey}}==
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