Data commit

Task/Cullen-and-Woodall-numbers/Java/cullen-and-woodall-numbers.java

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+import java.math.BigInteger;
+
+public final  class CullenAndWoodhall {
+
+	public static void main(String[] aArgs) {
+		numberSequence(20, NumberType.Cullen);
+		
+		numberSequence(20, NumberType.Woodhall);
+		
+		primeSequence(5, NumberType.Cullen);
+		
+		primeSequence(12, NumberType.Woodhall);
+	}
+
+	private enum NumberType { Cullen, Woodhall }
+	
+	private static void numberSequence(int aCount, NumberType aNumberType) {
+		System.out.println();
+		System.out.println("The first " + aCount + " " + aNumberType + " numbers are:");
+		numberInitialise();
+		for ( int index = 1; index <= aCount; index++ ) {
+			System.out.print(nextNumber(aNumberType) + " ");
+		}	
+		System.out.println();	
+	}
+	
+	private static void primeSequence(int aCount, NumberType aNumberType) {
+		System.out.println();
+		System.out.println("The indexes of the first " + aCount + " " + aNumberType + " primes are:");
+		primeInitialise();
+		
+		while ( count < aCount ) {			
+			if ( nextNumber(aNumberType).isProbablePrime(CERTAINTY) ) {
+				System.out.print(primeIndex + " ");
+				count += 1;
+			}
+			
+			primeIndex += 1;
+		}
+		System.out.println();
+	}
+	
+	private static BigInteger nextNumber(NumberType aNumberType) {
+		number = number.add(BigInteger.ONE);
+		power = power.shiftLeft(1);
+		return switch ( aNumberType ) {
+			case Cullen -> number.multiply(power).add(BigInteger.ONE);
+			case Woodhall -> number.multiply(power).subtract(BigInteger.ONE);
+		};
+	}
+	
+	private static void numberInitialise() {
+		number = BigInteger.ZERO;
+		power = BigInteger.ONE;		
+	}
+	
+	private static void primeInitialise() {	
+		count = 0;
+		primeIndex = 1;
+		numberInitialise();
+	}
+	
+	private static BigInteger number;
+	private static BigInteger power;
+	private static int count;
+	private static int primeIndex;
+	
+	private static final int CERTAINTY = 20;
+	
+}