Question5_2.java

/**
 * Given a real number between 0 and 1 (e.g., 0.72) that is passed in as a double, print the binary representation.
 * If the number cannot be represented accurately in binary with at most 32 characters, print "ERROR".
 * 
 * Time  Complexity: O(1)
 * Space Complexity: O(1)
 */

public class Question5_2 {
    public String binaryRepresentation(double value) {
        if (value >= 1 || value <= 0) {
            return "ERROR";
        }
        
        StringBuffer binary = new StringBuffer("0.");
        double subtractor = 0.5;
        while (binary.length() < 32 && value > 0.0) {
            if (value - subtractor >= 0) {
                value -= subtractor;
                binary.append(1);
            } else {
                binary.append(0);
            }
            subtractor /= 2;
        }
        
        return value <= 0 ? binary.toString() : "ERROR";
    }
    
    
    public static void main(String[] args) {
        Question5_2 question5_2 = new Question5_2();
        System.out.println(question5_2.binaryRepresentation(10));
        System.out.println(question5_2.binaryRepresentation(-10));
        System.out.println(question5_2.binaryRepresentation(0.75));
        System.out.println(question5_2.binaryRepresentation(0.125));
        System.out.println(question5_2.binaryRepresentation(0.00000000000000000000000125));
    }
}