A two-dimensional fail-soft array : Indexer : Class Interface C# Source Code

    

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/

// A two-dimensional fail-soft array. 
 
using System; 
 
class FailSoftArray2D {  
  int[,] a; // reference to underlying 2D array  
  int rows, cols; // dimensions 
  public int Length; // Length is public 
 
  public bool errflag; // indicates outcome of last operation 
   
  // Construct array given its dimensions. 
  public FailSoftArray2D(int r, int c) { 
    rows = r; 
    cols = c; 
    a = new int[rows, cols]; 
    Length = rows * cols;  
  } 
 
  // This is the indexer for FailSoftArray2D. 
  public int this[int index1, int index2] { 
    // This is the get accessor. 
    get { 
      if(ok(index1, index2)) { 
        errflag = false; 
        return a[index1, index2]; 
      } else { 
        errflag = true; 
        return 0; 
      } 
    } 
 
    // This is the set accessor. 
    set { 
      if(ok(index1, index2)) { 
        a[index1, index2] = value; 
        errflag = false; 
      } 
      else errflag = true; 
    } 
  } 
 
  // Return true if indexes are within bounds. 
  private bool ok(int index1, int index2) { 
   if(index1 >= 0 & index1 < rows & 
      index2 >= 0 & index2 < cols) 
         return true; 
 
   return false; 
  } 
}  
  
// Demonstrate a 2D indexer. 
public class TwoDIndexerDemo {  
  public static void Main() {  
    FailSoftArray2D fs = new FailSoftArray2D(3, 5); 
    int x; 
 
    // show quiet failures 
    Console.WriteLine("Fail quietly."); 
    for(int i=0; i < 6; i++) 
      fs[i, i] = i*10; 
 
    for(int i=0; i < 6; i++) { 
      x = fs[i,i]; 
      if(x != -1) Console.Write(x + " "); 
    } 
    Console.WriteLine(); 
 
    // now, generate failures 
    Console.WriteLine("\nFail with error reports."); 
    for(int i=0; i < 6; i++) { 
      fs[i,i] = i*10; 
      if(fs.errflag) 
        Console.WriteLine("fs[" + i + ", " + i + "] out-of-bounds"); 
    } 
 
    for(int i=0; i < 6; i++) { 
      x = fs[i,i]; 
      if(!fs.errflag) Console.Write(x + " "); 
      else 
        Console.WriteLine("fs[" + i + ", " + i + "] out-of-bounds"); 
    } 
  } 
}