get an Int from a byte array

[hansipet]

Hello,

is there an easy way as in C or c++ to get an integer from a byte array

c code

char test[4];

return (int)test;

Regards
Hansjörg

[Alex F]

First, C++ code is not correct, because it converts pointer to int. I would do this with union in C++.
C# contains FieldOffset attribute which allows to get the same functionality as C++ union.

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    [StructLayout( LayoutKind.Explicit)]
    struct MyUnion
    {
        [FieldOffset(0)] public byte byte1;
        [FieldOffset(1)] public byte byte2;
        [FieldOffset(2)] public byte byte3;
        [FieldOffset(3)] public byte byte4;
        [FieldOffset(0)] public int myInt;
    };

    class Program
    {
        static void Main(string[] args)
        {
            MyUnion u;
            u.myInt = 0;        // prevent compiler error

            u.byte1 = 0;
            u.byte2 = 1;
            u.byte3 = 0;
            u.byte4 = 0;

            Console.WriteLine(u.myInt); // result is 256 - Litle Endian machine
        }
    }
}

[Athley]

You say Byte array, but your example has char array...

But if you mean byte[] you could use the System.BitConverter.ToInt32() method.

/Leyan

[hansipet]

the second hint is great. It was really that what I needed.

Shame on me for c code....

Regards
Hansjörg

[hansipet]

Is it also possible to convert the data to bigEndian?

[Andy Tacker]

look for Encoding class, hansipet!

[GoDaddy]

do some shifting to turn littleendian to bigendian :P