how define (number range) enum in c#

hamed hossani

hi all
I define the type with ENUM in number range [1-n] n is the Maximum number.
I will define this range to specify the array.

string[] array1=new string[1-n] // means start index for this array is 1 and finish index is n
how define this range?

similar this Pascal code[partion of algorithm Buddy System Allocation memory]

CONST NULL = -1;
TYPE address: NULL..m;
   sizeindex: 1..n;
VAR
   size : array[sizeindex] of 1..m;
   subbuddy : array[sizeindex] of 0..n;
   memory : array[0..m] of paced record
   tag: (available,allocated);
   a,b: (left,right):
   index: sizeindex;
   forward: address;
   backward: address;
   end;

tanks a lot.

3 Replies

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Vulpes15y ago
That's fine if you're just doing a simulation.

I thought you might be hoping to allocate managed memory 'for real' :)
hamed hossani15y ago
hi
I create simulation of buddy system allocation memory,very simple,based on this pdf(section 2 only)[http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.79.6369&rep=rep1&type=pdf]
it,s display the process that input,we added input process and display into DataGridView,finally display added process to a PictureBox.
this is project for lab OS.
similar this link:
http://www.codeproject.com/KB/threads/PriorityQueueGeneric.aspx

tanks
Vulpes15y ago
In .NET all arrays have a lower bound of zero by default.

It's possible to define arrays with different lower bounds but they are inefficient and C# doesn't have any special syntax to deal with them. However, here's how you'd define a single dimensional array of ints with a lower bound of 1 and an upper bound of n which is linked to an enum value:

using System;

enum Range
{
   One = 1,
   Two,
   Three,
   Four,
   Five
}

class Test
{
   static void Main()
   {
   int n = (int)Range.Five;
   int[] lengths = new int[1]{n};
   int[] lowerBounds = new int[1]{1};
   Array oneBased = Array.CreateInstance(typeof(int), lengths, lowerBounds);

   // populate array with ints from 1 to n
   // can't use oneBase[i] = i syntax for this
   for(int i = 1; i <= oneBased.Length; i++)
   {
   oneBased.SetValue(i,i);
   }

   // iterate through array
   foreach(int i in oneBased) Console.Write("{0} ", i);
   Console.WriteLine();

   // get value at a particular index
   int j = (int)oneBased.GetValue((int)Range.Three);
   Console.WriteLine(j);
   Console.ReadKey();
   }
}

Also, it's not possible to do your own managed memory allocation in .NET - the system does it automatically for you.

The nearest we have to the Buddy system are dymamic collections such as List which use an array of T as a backing store and double the size of this store, as needed, when new elements are added.

If you're wanting to do your own memory allocation in a language other than Pascal, then the best option is C/C++ though you can use C# to create an unmanaged memory block (Marshal.AllocHGlobal) and then use pointers (in unsafe code) to manipulate it.