Use an indexer to create a fail-soft array
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Use an indexer to create a fail-soft array.
using System;
class FailSoftArray {
int[] a; // reference to underlying array
public int Length; // Length is public
public bool errflag; // indicates outcome of last operation
// Construct array given its size.
public FailSoftArray(int size) {
a = new int[size];
Length = size;
}
// This is the indexer for FailSoftArray.
public int this[int index] {
// This is the get accessor.
get {
if(ok(index)) {
errflag = false;
return a[index];
} else {
errflag = true;
return 0;
}
}
// This is the set accessor
set {
if(ok(index)) {
a[index] = value;
errflag = false;
}
else errflag = true;
}
}
// Return true if index is within bounds.
private bool ok(int index) {
if(index >= 0 & index < Length) return true;
return false;
}
}
// Demonstrate the fail-soft array.
public class FSDemo {
public static void Main() {
FailSoftArray fs = new FailSoftArray(5);
int x;
// show quiet failures
Console.WriteLine("Fail quietly.");
for(int i=0; i < (fs.Length * 2); i++)
fs[i] = i*10;
for(int i=0; i < (fs.Length * 2); i++) {
x = fs[i];
if(x != -1) Console.Write(x + " ");
}
Console.WriteLine();
// now, generate failures
Console.WriteLine("\nFail with error reports.");
for(int i=0; i < (fs.Length * 2); i++) {
fs[i] = i*10;
if(fs.errflag)
Console.WriteLine("fs[" + i + "] out-of-bounds");
}
for(int i=0; i < (fs.Length * 2); i++) {
x = fs[i];
if(!fs.errflag) Console.Write(x + " ");
else
Console.WriteLine("fs[" + i + "] out-of-bounds");
}
}
}
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