Question

I am creating a binary file, for this I am using

namespace BinaryStream
{
    class Program
    {
        static void Main(string[] args)
        {
            string filename = @"c:\happybirthday.txt";
            using (BinaryWriter binWriter =
    new BinaryWriter(File.Open(filename, FileMode.Create)))
            {
                string name = "Sachin";
                string wishes = "happy birthday";

                binWriter.Write(name.ToCharArray());
                binWriter.Write(wishes.ToCharArray());
            }



        }
    }
}

if binWriter.Writer(name) is used the file contains some special characters. But if i convert the string to chararray and write to file , the file contains the normal text(without any special characters).

What is the reason behind this?

Answer 1

The Write(string) overload is length prefixed:

From here: http://msdn.microsoft.com/en-us/library/yzxa6408.aspx

A length-prefixed string represents the string length by prefixing to
the string a single byte or word that contains the length of that
string. This method first writes the length of the string as a UTF-7
encoded unsigned integer, and then writes that many characters to the
stream by using the BinaryWriter instance’s current encoding.

Whereas Write(char[]) is not. That extra information will show up as weird data when opened with text viewing.

The reason for this is obvious when looking at read behaviour. BinaryReader.ReadChars needs to be told how many chars to read, while BinaryReader.ReadString works it out by looking at the length prefix.

Edit: Possible duplicate, extra info anyway: Difference in writing string vs. char array with System.IO.BinaryWriter