CoinFlip

gistfile1.java

package de.mukis;

import java.text.DecimalFormat;
import java.text.NumberFormat;

/**
 * Generates all possibilities for a coinflip.
 * 
 * @author muki
 *
 */
public class CoinFlip {

    private final NumberFormat formatter = DecimalFormat.getIntegerInstance();

    /**
     * Prints all possible outcomes of a coinflip for n trials
     * @param n
     */
    public void printPermutations(int n) {
        formatter.setMinimumIntegerDigits(toBinaryString(n).length());
        int possibilities = (int) Math.pow(2, n);
        for (int i = 0; i < possibilities; i++) {
            System.out.println(formatPermutation(i));
        }
    }

    /**
     * 
     * @param i
     * @return a formatted string for one permutation step
     */
    private String formatPermutation(int i) {
        return i + "\t " + formatter.format(toBinary(i));
    }
    
    /**
     * 
     * @param decimal
     * @return an binary integer (contains only 0 and 1) 
     */
    private long toBinary(int decimal) {
        return Integer.valueOf(toBinaryString(decimal));
    }

    /**
     * 
     * @param decimal
     * @return a binary representation of the decimal value as string
     */
    private String toBinaryString(int decimal) {
        return Integer.toBinaryString(decimal);
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        CoinFlip coinFlip = new CoinFlip();
        coinFlip.printPermutations(5);
    }

}