C - C++ Pointers - NULL pointer

#include <iostream.h>
 
int main () 
{
  try
  {
    char * mystring;
    mystring = new char [10];
    if (mystring == NULL) 
      throw "Allocation failure";
 
    for (int n=0; n<=100; n++)
    {
      if (n>9) 
         throw n;
 
      mystring[n]='a';
    }
  }
  catch (int i)
  {
    cout << "index " << i << " is out of range" << endl;
  }
  catch (char * str)
  {
    cout << "Exception: " << str << endl;
  }
 
  return 0;
}