Generator/Exponential: Difference between revisions

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

Note that types have been made static and variables made explicit as an aid to understanding.

'''Closure Style'''

<lang csharp>using System;

using System.Collections.Generic;

using System.Linq;

namespace RosettaGenerator

{

class ClosureStyle

{

static void Main(string[] args)

{

Func<int> squaresGenerator = PowerGeneratorAsClosure(2);

Func<int> cubesGenerator = PowerGeneratorAsClosure(3);

Func<int> filter = FilterAsClosure(squaresGenerator, cubesGenerator);

foreach (int i in Enumerable.Range(0, 20))

filter();

foreach (int i in Enumerable.Range(21, 10))

Console.Write(filter() + " ");

Console.WriteLine();

}

public static Func<int> PowerGeneratorAsClosure(int exponent)

{

int x = 0;

return () => { return (int)Math.Pow(x++, exponent); };

}

public static Func<int> FilterAsClosure(Func<int> squaresGenerator, Func<int> cubesGenerator)

{

int value;

int filter = cubesGenerator();

return () =>

{

while (true)

{

value = squaresGenerator();

while (value > filter)

filter = cubesGenerator();

if (value < filter)

return value;

}

};

}

}

}</lang>

'''List Style'''

<lang csharp>using System;

using System.Collections.Generic;

using System.Linq;

namespace RosettaGenerator

{

class ListStyle

{

static void Main(string[] args)

{

IEnumerator<int> squaresGenerator = PowerGeneratorAsList(2);

IEnumerator<int> cubesGenerator = PowerGeneratorAsList(3);

IEnumerable<int> filter = FilterAsList(squaresGenerator, cubesGenerator);

foreach (int value in filter.Skip(20).Take(10))

Console.Write(value + " ");

Console.WriteLine();

}

public static IEnumerator<int> PowerGeneratorAsList(int exponent)

{

int x = 0;

while (true)

yield return (int)Math.Pow(x++, exponent);

}

public static IEnumerable<int> FilterAsList(IEnumerator<int> squaresGenerator, IEnumerator<int> cubesGenerator)

{

int value;

int filter = cubesGenerator.Current;

while (true)

{

value = squaresGenerator.Current;

while (value > filter)

{

cubesGenerator.MoveNext();

filter = cubesGenerator.Current;

}

if (value < filter)

yield return value;

squaresGenerator.MoveNext();

}

}

}

}</lang>

Output (for either):

<pre>529 576 625 676 784 841 900 961 1024 1089</pre>