打印0-1之间double数字的二进制表示

public class Solution {

    public static String printBinary(double num) {
        if (num >= 1 || num <= 0)
            return "ERROR";

        StringBuilder res = new StringBuilder();
        res.append(‘.‘);
        double frac = 0.5;
        while (num > 0) {
            if (res.length() >= 32)
                return "ERROR";

            if (num >= frac) {
                res.append(1);
                num -= frac;
            } else {
                res.append(0);
            }
            frac /= 2;
        }

        return res.toString();

    }

    public static void main(String[] args) {
        System.out.println(printBinary(0.875));
    }
}