import java.io.*;

class UseCharListsA6
{
// Shows destructive append and change on lists
// using recursion

 public static void main(String[] args) throws IOException
 {
  BufferedReader in = new BufferedReader(
                        new InputStreamReader(System.in));
  CharListA L1=null,L2=null;
  char ch1,ch2;
  try {
       System.out.print("Enter first list of characters: ");
       L1 = CharListAIO.read(in);
       System.out.print("Enter second list of characters: ");
       L2 = CharListAIO.read(in);
      }
  catch(ListFormatException e)
      {
       System.out.println("Error: "+e.getMessage());
      }
  System.out.print("The lists are: ");
  CharListAIO.print(L1);
  System.out.print(" and ");
  CharListAIO.print(L2);
  System.out.println();
  System.out.println("Call destructive append ");
  destAppend(L1,L2);
  System.out.print("The lists are now: ");
  CharListAIO.print(L1);
  System.out.print(" and ");
  CharListAIO.print(L2);
  System.out.println();
  System.out.print("Enter first character: ");
  ch1=in.readLine().charAt(0);
  System.out.print("Enter second character: ");
  ch2=in.readLine().charAt(0);
  System.out.print("Call destructive change of first to ");
  System.out.println("second character");
  System.out.println("in second list ");
  destChange(ch1,ch2,L2);
  System.out.print("The lists are now: ");
  CharListAIO.print(L1);
  System.out.print(" and ");
  CharListAIO.print(L2);
  System.out.println();
 }

 public static void destAppend(CharListA L1,CharListA L2)
 {
  if(L1.tail!=null)
     destAppend(L1.tail,L2);
  else
     L1.tail=L2;
 }

 public static void destChange(char ch1,char ch2,CharListA L)
 {
  if(L!=null)
     {
      destChange(ch1,ch2,L.tail);
      if(L.head==ch1)
         L.head=ch2;
     }
 }

}