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Exercise solution:
Revealing the propagation of exceptions

Here is my solution:

using System;

class ExceptionDemo{

  public static void Main(){
    int[] table = new int[6]{10,11,12,13,14,15};
    int idx = 6;

    Console.WriteLine("Main");
    try{
      M(table, idx);
    }   
    catch (IndexOutOfRangeException){
      M(table, AdjustIndex(idx,0,5));
    }
  }

  public static void M(int[] table, int idx){
    Console.WriteLine("Calling M(table,{0})", idx);
    try{
      N(table,idx);}
    catch {
      Console.WriteLine("Reversing through M");
      throw;
    }
  }

  public static void N(int[] table, int idx){
    Console.WriteLine("Calling N(table,{0})", idx);
    try {
      P(table,idx);}
    catch {
      Console.WriteLine("Reversing through N");
      throw;
    }
  }

  public static void P(int[] table, int idx){
    Console.WriteLine("Calling P(table,{0})", idx);
    try {
      Console.WriteLine("Accessing element {0}: {1}", 
                         idx, table[idx]);
    }
    catch {
      Console.WriteLine("Error in P. Reversing through P");
      throw;
    }
  }


  public static int AdjustIndex(int i, int low, int high){
    int res;
    if (i < low)
      res = low;
    else if (i > high)
      res = high;
    else res = i;

    return res;
  }
}

Notice the use of catch without specifying the type or name of the exception.

The output of the program is here:

Main
Calling M(table,6)
Calling N(table,6)
Calling P(table,6)
Error in P. Reversing through P
Reversing through N
Reversing through M
Calling M(table,5)
Calling N(table,5)
Calling P(table,5)
Accessing element 5: 15

Exercise solution: Revealing the propagation of exceptions

Exercise solution:
Revealing the propagation of exceptions