Use an indexer to create a fail-soft array. : Indexer « Class « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Class
3. Indexer

using System; 
 
class MyArray {  
  int[] a;
 
  public int Length; 
 
  public bool errflag;
   
  public MyArray(int size) { 
    a = new int[size]; 
    Length = size;  
  } 
 
  // This is the indexer for MyArray. 
  public int this[int index] { 
    get { 
      if(indexCheck(index)) { 
        errflag = false; 
        return a[index]; 
      } else { 
        errflag = true; 
        return 0; 
      } 
    } 
 
    set { 
      if(indexCheck(index)) { 
        a[index] = value; 
        errflag = false; 
      } 
      else errflag = true; 
    } 
  } 
 

  private bool indexCheck(int index) { 
   if(index >= 0 & index < Length) 
      return true; 
   return false; 
  } 
}  
  
class MainClass {  
  public static void Main() {  
    MyArray myArray = new MyArray(5); 
    int x; 
 
    Console.WriteLine("Fail quietly."); 
    for(int i=0; i < 10; i++) 
      myArray[i] = i*10; 
 
    for(int i=0; i < 10; i++) { 
      x = myArray[i]; 
      if(x != -1) Console.Write(x + " "); 
    } 
    Console.WriteLine(); 
 
    Console.WriteLine("\nFail with error reports."); 
    for(int i=0; i < 10; i++) { 
      myArray[i] = i*10; 
      if(myArray.errflag) 
        Console.WriteLine("myArray[" + i + "] out-of-bounds"); 
    } 
 
    for(int i=0; i < 10; i++) { 
      x = myArray[i]; 
      if(!myArray.errflag) 
         Console.Write(x + " "); 
      else 
         Console.WriteLine("myArray[" + i + "] out-of-bounds"); 
    } 
  } 
}

Fail quietly.
0 10 20 30 40 0 0 0 0 0

Fail with error reports.
myArray[5] out-of-bounds
myArray[6] out-of-bounds
myArray[7] out-of-bounds
myArray[8] out-of-bounds
myArray[9] out-of-bounds
0 10 20 30 40 myArray[5] out-of-bounds
myArray[6] out-of-bounds
myArray[7] out-of-bounds
myArray[8] out-of-bounds
myArray[9] out-of-bounds