//引入命名空间
using System;
using System.Text;

class ASCIIEncodingExample {
    public static void Main() {
        // The encoding.
        ASCIIEncoding ascii = new ASCIIEncoding();
        
        // A Unicode string with two characters outside the ASCII code range.
        String unicodeString =
            "This Unicode string contains two characters " +
            "with codes outside the ASCII code range, " +
            "Pi (\u03a0) and Sigma (\u03a3).";
        Console.WriteLine("Original string:");
        Console.WriteLine(unicodeString);

        // Save positions of the special characters for later reference.
        int indexOfPi = unicodeString.IndexOf('\u03a0');
        int indexOfSigma = unicodeString.IndexOf('\u03a3');

        // Encode string.
        Byte[] encodedBytes = ascii.GetBytes(unicodeString);
        Console.WriteLine();
        Console.WriteLine("Encoded bytes:");
        foreach (Byte b in encodedBytes) {
            Console.Write("[{0}]", b);
        }
        Console.WriteLine();
        
        // Notice that the special characters have been replaced with
        // the value 63, which is the ASCII character code for '?'.
        Console.WriteLine();
        Console.WriteLine(
            "Value at position of Pi character: {0}",
            encodedBytes[indexOfPi]
        );
        Console.WriteLine(
            "Value at position of Sigma character: {0}",
            encodedBytes[indexOfSigma]
        );

        // Decode bytes back to string.
        // Notice missing Pi and Sigma characters.
        String decodedString = ascii.GetString(encodedBytes);
        Console.WriteLine();
        Console.WriteLine("Decoded bytes:");
        Console.WriteLine(decodedString);
    }
}

//引入命名空间
using System;
using System.Text;

class StringEncodingApp {
    static void Main(string[] args) {
        ASCIIEncoding ae = new ASCIIEncoding();
        Console.WriteLine(ae.GetString(new byte[]{1,2,3}));
        UnicodeEncoding bu = new UnicodeEncoding(true, false);
        Console.WriteLine(bu.GetString(new byte[]{1,2,3}));
    }
}