[英]Convert.ToString() to binary format not working as expected
int i = 20;
string output = Convert.ToString(i, 2); // Base2 formatting
i = -20;
output = Convert.ToString(i, 2);
Value Expected Actual 20 00000000000000000000000000010100 10100 -20 10000000000000000000000000010100 11111111111111111111111111101100
I can see that perhaps the binary output of 20 has been truncated but I do not understand the output for -20.我可以看到,也许 20 的二进制 output 已被截断,但我不明白 -20 的 output。 I based my expectations on base2 notation plus a belief that the signed element of an integer was expressed in the first left most digit.
我的期望基于 base2 符号加上一个信念,即 integer 的有符号元素用最左边的第一个数字表示。 0 for positive and 1 for negative.
0 表示正,1 表示负。 Can someone explain the results, specifically that of -20?
有人可以解释结果,特别是-20的结果吗?
Negative numbers in .NET are represented in binary as Two's complement . .NET 中的负数以二进制表示为二进制补码。
From MSDN - Convert.ToString Method (Int32, Int32) :来自 MSDN - Convert.ToString 方法(Int32,Int32) :
If value is negative and toBase is 2, 8, or 16, the returned string uses two's complement representation
如果 value 为负且 toBase 为 2、8 或 16,则返回的字符串使用二进制补码表示
for integer -20 is 11111111111111111111111111101100 System is using 2's Complement by default.对于 integer -20 为 11111111111111111111111111101100 系统默认使用 2 的补码。 1's Complement is not ideal for calculation.
1 的补码不适合计算。
(2's complement is invert of all bit plus one) (2 的补码是所有位加一的反转)
in 2's Complement, which will make 20 + (-20) = 0, can compute math easily without concern positive or negative.在 2 的补码中,这将使 20 + (-20) = 0,可以轻松计算数学,而无需担心正负。
for example, in signed char: 15 = 00001111, -18 = 2's Complement of (00010010) = 11101101 + 1 = 11101110例如,在有符号字符中:15 = 00001111,-18 = (00010010) 的 2 补码 = 11101101 + 1 = 11101110
00001111 +11101110 =11111101 00001111 +11101110 =11111101
Since first bit is 1, we know it is a negative value.由于第一位是 1,我们知道它是一个负值。 Let's do a reverse 2's Complement.
让我们做一个反向 2 的补码。
11111101 - 1 = 11111100 => -(00000011) it gives -3 which 15 + (-18) = -3 11111101 - 1 = 11111100 => -(00000011) 它给出 -3 其中 15 + (-18) = -3
int value = 31;
string binary = Convert.ToString(value, 2);
Console.WriteLine(binary.PadLeft(8, '0')); // Outputs "00011111"
This is basically the same answer as everyone else has posted, just packaged in a method.这与其他所有人发布的答案基本相同,只是打包在一个方法中。
/// <summary>
/// Method to convert an integer to a string containing the number in binary. A negative
/// number will be formatted as a 32-character binary number in two's compliment.
/// </summary>
/// <param name="theNumber">self-explanatory</param>
/// <param name="minimumDigits">if binary number contains fewer characters leading zeros are added</param>
/// <returns>string as described above</returns>
public static string IntegerToBinaryString(int theNumber, int minimumDigits)
{
return Convert.ToString(theNumber, 2).PadLeft(minimumDigits, '0');
}
This function does exactly what you want这个 function 完全符合您的要求
string ConvertToFuzzyFrogBinary(int input)
{
int prefix = (input).ToString("d8").Length-(Math.Abs((input))).ToString("d8").Length;
string binary_num = "00000000000000000000000000000000".Substring(0,32-Convert.ToString(Math.Abs(input),2).Length)+Convert.ToString(Math.Abs(input),2);
return "1".Substring(0,prefix)+binary_num.Substring(prefix,32-prefix);
}
Here is a routine I wrote that does what the original questioner wanted.这是我写的一个例程,它可以满足原始提问者的要求。 A mere 5 years too late!
仅仅晚了5年!
/// <summary>Convert a number into a string of bits</summary>
/// <param name="value">Value to convert</param>
/// <param name="minBits">Minimum number of bits, usually a multiple of 4</param>
/// <exception cref="InvalidCastException">Value must be convertible to long</exception>
/// <exception cref="OverflowException">Value must be convertible to long</exception>
/// <returns></returns>
public static string ShowBits<T>(this T value, int minBits)
{
long x = Convert.ToInt64(value);
string retVal = Convert.ToString(x, 2);
if (retVal.Length > minBits) retVal = Regex.Replace(retVal, @"^1+", "1"); // Replace leading 1s with a single 1 - can pad as needed below
if (retVal.Length < minBits) retVal = new string(x < 0 ? '1' : '0', minBits - retVal.Length) + retVal; // Pad on left with 0/1 as appropriate
return retVal;
}
If you would get rid of this "effect" - use Math.Abs()
method to get number value without sign,如果你想摆脱这种“影响” - 使用
Math.Abs()
方法来获取没有符号的数值,
string output = Convert.ToString(Math.Abs(i), 2); // Base2
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