从double到byte数组的转换，反之亦然

Question

i want to convert double array to byte array and byte array to double array

using System.Collections.Generic;
using System.Collections;
using System.Text;
using System.Linq;


namespace BitConversion
{
    class Program
    {
        static void Main(string[] args)
        {
            double[] Array = new double[] { 10.0, 20.0, 30.0, 40.0 };
            byte[] byteArray = GetBytesAlt(Array);
            for (int i = 0; i < byteArray.Length; i++)
            {
                Console.Write(byteArray[i]);
                Console.Write(",");

            }

            Console.WriteLine();

            double[] doubleArray = GetDoublesAlt(byteArray);
            for (int i = 0; i < doubleArray.Length; i++)
            {
                Console.Write(doubleArray[i]);
                Console.Write(",");
            }

            Console.WriteLine();

            Console.ReadLine();
        }

        /// <summary>
        /// convert to bytes
        /// </summary>
        /// <param name="values"></param>
        /// <returns></returns>
        static byte[] GetBytesAlt(double[] values)
        {
            /*var result = new byte[values.Length * sizeof(double)];
            Buffer.BlockCopy(values, 0, result, 0, result.Length); 
            return result;*/

            return values.SelectMany(value => BitConverter.GetBytes(value)).ToArray();

            //return values.SelectMany(value => BitConverter.GetBytes(value)).ToArray(); 

        }

        static double[] GetDoublesAlt(byte[] bytes)
        {
           /* var result = new double[bytes.Length / sizeof(double)];
            Buffer.BlockCopy(bytes, 0, result, 0, bytes.Length);
            return result;*/
            return Enumerable.Range(0, bytes.Length / sizeof(double)).Select(offset => BitConverter.ToDouble(bytes, offset * sizeof(double))).ToArray(); 

        }
    }
}

with the convert approach the when bytes are converted back to the doubles the numbers are getting as 10.0,20.0, 30.0, 40.0.....

How to get back the same numbers?

I mean if the double entered is 10.0, 20.0 , 30.0 , 40.0 and i have get back the same number is 10.0,20.0,30.0,40.0.

Answer 1

There is no issue with your program - if you slightly modify your program and print the original as well as round-tripped array, you will indeed see that you get the same out-put. For example,

Original:       10.1,20.2,30,40,
Round-trip:     10.1,20.2,30,40,

Here's the slightly modified code

    class Program
    {
        static void Main(string[] args)
        {
            double[] Array = new double[] { 10.1, 20.2, 30.0, 40.0 };
            Console.Write("Original:\t");
            PrintArray(Array);

            byte[] byteArray = GetBytesAlt(Array);
            double[] doubleArray = GetDoublesAlt(byteArray);
            Console.Write("Round-trip:\t");
            PrintArray(doubleArray);

            Console.ReadLine();
        }

        static void PrintArray(Double[] array)
        {
            for (int i = 0; i < array.Length; i++)
            {
                Console.Write(array[i]);
                Console.Write(",");
            }
            Console.WriteLine();
        }

            // rest of methods are same
            ...
     }

Answer 2

You are getting the correct numbers, it is only in writing to the console that you are loosing your .0 the two numbers are equivalant. 10.0 and 10. This is what your doubleArray looks like before writing.

Try changing your Console.Write statement to this:

for (int i = 0; i < doubleArray.Length; i++)
    {
      //Since you are forcing the .0 you need to make sure you have enough #'s 
      //for the level of precision you need. It is actually better to use the 
      //system default since 10.0 and 10 are functionaly equivalent.

        Console.Write( doubleArray[i].ToString("##.0####")); 
        Console.Write(",");
    }