将Double转换为二进制表示?

问题描述 投票:11回答:5

我试图将double转换为它的二进制表示,但使用这个Long.toBinaryString(Double.doubleToRawLongBits(d))没有帮助,因为我有大数字,Long不能存储它们,即2^900

java binary double type-conversion long-integer
5个回答
25
投票

Long.toBinaryString(Double.doubleToRawLongBits(d))似乎工作得很好。

System.out.println("0:                0b" + Long.toBinaryString(Double.doubleToRawLongBits(0D)));
System.out.println("1:                0b" + Long.toBinaryString(Double.doubleToRawLongBits(1D)));
System.out.println("2:                0b" + Long.toBinaryString(Double.doubleToRawLongBits(2D)));
System.out.println("2^900:            0b" + Long.toBinaryString(Double.doubleToRawLongBits(Math.pow(2, 900))));
System.out.println("Double.MAX_VALUE: 0b" + Long.toBinaryString(Double.doubleToRawLongBits(Double.MAX_VALUE)));

/*
    prints:
    0:                0b0
    1:                0b11111111110000000000000000000000000000000000000000000000000000
    2:                0b100000000000000000000000000000000000000000000000000000000000000
    2^900:            0b111100000110000000000000000000000000000000000000000000000000000
    Double.MAX_VALUE: 0b111111111101111111111111111111111111111111111111111111111111111
*/

4
投票

您可能想要处理整个和小数部分:

public String toBinary(double d, int precision) {
    long wholePart = (long) d;
    return wholeToBinary(wholePart) + '.' + fractionalToBinary(d - wholePart, precision);
}

private String wholeToBinary(long l) {
    return Long.toBinaryString(l);
}

private String fractionalToBinary(double num, int precision) {
    StringBuilder binary = new StringBuilder();
    while (num > 0 && binary.length() < precision) {
        double r = num * 2;
        if (r >= 1) {
            binary.append(1);
            num = r - 1;
        } else {
            binary.append(0);
            num = r;
        }
    }
    return binary.toString();
}

1
投票

您可以使用BigInteger来保存您的大数字和BigInteger.toString()方法来检索它的二进制表示。

BigInteger bigNum = new BigInteger(sYourNum);
System.out.println( bigNum.toString(2) );

0
投票

您是否尝试过使用java.math.BigInteger并使用参数2调用toString(int radix)


-1
投票

您可以使用Double.toHexString(d),然后使用for循环和StringBuilder将十六进制字符串转换为二进制字符串。

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