Data Representation HW

BinaryAddition.java

package nyc.c4q.ramonaharrison;

/**
 * Access Code 2.1
 * Ramona Harrison
 */

public class BinaryAddition {
    public static void main(String[] args) {
        String s1 = Integer.toString(134,2);
        String s2 = Integer.toString(562,2);
        System.out.println(addBinaryNumbers(s1, s2));

        String s3 = Integer.toString(51,2);
        String s4 = Integer.toString(-8,2);
        System.out.println(addBinaryNumbers(s3, s4));

        System.out.println(Integer.toOctalString(52));
    }

    public static String addBinaryNumbers(String binary1, String binary2) {
        if (binary1 == null || binary2 == null) return "";
        int first = binary1.length() - 1;
        int second = binary2.length() - 1;
        StringBuilder stringBuilder = new StringBuilder();
        int carry = 0;
        while (first >= 0 || second >= 0) {
            int sum = carry;
            if (first >= 0) {
                sum += binary1.charAt(first) - '0';
                first--;
            }
            if (second >= 0) {
                sum += binary2.charAt(second) - '0';
                second--;
            }
            carry = sum >> 1;
            sum = sum & 1;
            stringBuilder.append(sum == 0 ? '0' : '1');
        }
        if (carry > 0)
            stringBuilder.append('1');


        stringBuilder.reverse();
        return String.valueOf(stringBuilder);
    }

    public static int countOnes(String bitstring) {
        int ones = 0;
        for (int i = 0; i < bitstring.length(); i++) {
            if (bitstring.charAt(i) == '1') {
                ones++;
            }
        }
        return ones;
    }

    public static boolean isPalindrome(String bitstring) {
        return bitstring.equals(new StringBuilder(bitstring).reverse().toString());
    }
}