複素数偏角でFizzBuzz 元ネタ：Fizzbuzz in Complex Plane http://www.slideshare.net/KaoruMaeda/fizzbuzz-16341544 (2013/02/11 フォーマットでswitchを消せることに気付き fizzbuzz2 メソッドを追記)

ComplexArgFizzBuzz.java

import org.apache.commons.math3.complex.Complex;

public class ComplexArgFizzBuzz {

	public String fizzbuzz(int n) {
		Complex c = new Complex(-n % 5, n % 3);
		int index = (int) c.getArgument();
		String[] fizzbuzz = { "Fizzbuzz", "Buzz", "(^^", "Fizz" };
		switch (index) {
		case 2:
			return String.valueOf(n);
		default:
			return fizzbuzz[index];
		}
	}
	
	public String fizzbuzz2(int n) {
		String[] fizzbuzz = { "Fizzbuzz", "Buzz", "%d", "Fizz" };
		return String.format(fizzbuzz[(int) Complex.valueOf(-n % 5, n % 3).getArgument()], n);
	}
}

ComplexArgFizzBuzzTest.java

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import org.junit.Test;

public class ComplexArgFizzBuzzTest {

	@Test
	public void testFizzbuzz() {
		ComplexArgFizzBuzz target = new ComplexArgFizzBuzz();
		
		assertThat(target.fizzbuzz(1), is("1"));
		assertThat(target.fizzbuzz(2), is("2"));
		assertThat(target.fizzbuzz(3), is("Fizz"));
		assertThat(target.fizzbuzz(4), is("4"));
		assertThat(target.fizzbuzz(5), is("Buzz"));
		assertThat(target.fizzbuzz(6), is("Fizz"));
		assertThat(target.fizzbuzz(7), is("7"));
		assertThat(target.fizzbuzz(8), is("8"));
		assertThat(target.fizzbuzz(9), is("Fizz"));
		assertThat(target.fizzbuzz(10), is("Buzz"));
		assertThat(target.fizzbuzz(11), is("11"));
		assertThat(target.fizzbuzz(12), is("Fizz"));
		assertThat(target.fizzbuzz(13), is("13"));
		assertThat(target.fizzbuzz(14), is("14"));
		assertThat(target.fizzbuzz(15), is("Fizzbuzz"));
	}
}

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