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Ethiopian multiplication: Difference between revisions
→{{header|C sharp|C#}}
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=={{header|C sharp|C#}}==
int total = 0;▼
{{works with|c sharp|C#|3+}}<br>
{{libheader|System.Linq}}<br>
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{
Console.WriteLine ( "Ethiopian Multiplication" );
int A =
Console.WriteLine ( "Recursion: {0}*{1}={2}", A, B, EM_Recursion ( A, B ) );
Console.WriteLine ( "Linq: {0}*{1}={2}", A, B, EM_Linq ( A, B ) );
Console.WriteLine ( "Loop: {0}*{1}={2}", A, B, EM_Loop ( A, B ) );
Console.WriteLine ( );
}
Line 478 ⟶ 437:
public static int EM_Recursion ( int p_NumberA, int p_NumberB )
{
// Anchor Point, Recurse to find the next row Sum it with the second number according to the rules
return p_NumberA == 1 ? p_NumberB : EM_Recursion ( p_NumberA.Halve ( ), p_NumberB.Double ( ) ) + ( p_NumberA.IsEven ( ) ? 0 : p_NumberB );
}
public static int EM_Linq ( int p_NumberA, int p_NumberB )
{
// Creating a range from 1 to x where x the number of times p_NumberA can be halved.
// This will be 2^x where 2^x <= p_NumberA. Basically, ln(p_NumberA)/ln(2).
return Enumerable.Range ( 1, Convert.ToInt32 ( Math.Log ( p_NumberA, Math.E ) / Math.Log ( 2, Math.E ) ) + 1 )
// For every item (Y) in that range, create a new list, comprising the pair (p_NumberA,p_NumberB) Y times.
.Select ( ( item ) => Enumerable.Repeat ( new { Col1 = p_NumberA, Col2 = p_NumberB }, item )
// The aggregate method iterates over every value in the target list, passing the accumulated value and the current item's value.
.Aggregate ( ( agg_pair, orig_pair ) => new { Col1 = agg_pair.Col1.Halve ( ), Col2 = agg_pair.Col2.Double ( ) } ) )
// Remove all even items
.Where ( pair => !pair.Col1.IsEven ( ) )
// And sum!
.Sum ( pair => pair.Col2 );
}
public static int EM_Loop ( int p_NumberA, int p_NumberB )
{
while ( p_NumberA >= 1 )
{
RetVal += p_NumberA.IsEven ( ) ? 0 : p_NumberB;
p_NumberA = p_NumberA.Halve ( );
p_NumberB = p_NumberB.Double ( );
}
return RetVal;
}
}
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