/* FILE NAME: LabOpsIteration.java
 * AUTHOR: Stella K.
 *
 * DATE: Nov 3, 07
 *
 * COMMENTS: Solutions to lab methods on StringLists using iteration (tail rec, while and for-loops).
 * Notice that this class extends StringListOps, which extends StringList.
 * Therefore, all methods defined in these two classes are inhereted here.
 * 
 * In particular:
 * The following methods are inherited from StringList:
 * public static StringList empty();
 * public static boolean isEmpty (StringList L);
 * public static StringList prepend (String s, StringList L);
 * public static String head (StringList L);
 * public static StringList tail (StringList L);
 * public static boolean equals (StringList L1, StringList L2);
 * public static String toString (StringList L);
 * public static String fromString (String s);
 * 
 * The following methods are inherited from StringList:
 * public static int length (StringList L);
 * public static StringList append (StringList L1, StringList L2);
 * public static StringList postpend (StringList L, String s);
 * public static StringList reverse (StringList L);
 * 
 * All the above methods can be used in this file without the explicit 
 * "StringList." or "StringListOps." prefixes.
 * For example, you can write "head(L)" rather than "StringList.head(L)",
 * and "length(L)" rather than "StringListOps.length(L)".
 * 
 * MODIFICATION HISTORY:
*/    

public class LabOpsIteration extends StringListOps {
 // Write your methods here:
 
 
  
   public static void main (String [] args) {
 /*
     //testing the f=given auxiliary methods
  System.out.println("first(\"cs111\") = \"" + first("cs111") + "\"");
  System.out.println("butFirst(\"cs111\") = \"" + butFirst("cs111") + "\"");
  System.out.println("fromString(\"[I,do,not,like,green,eggs,and,ham]\") = "
                      + fromString("[I,do,not,like,green,eggs,and,ham]"));  
    // Add your testing code here:
  
  */   
     
  //Lists for testing
  StringList  testList0 = empty();
  StringList  testList1 = prepend("person", empty());
  StringList  testList2 = prepend("cat", prepend("desk", empty()));
  StringList  testList3 = prepend("hello", prepend("low", prepend("sun", empty())));
  StringList  testList8 = fromString(("[I,do,not,like,green,eggs,and,ham]"));
  
  //Testing isMemberRec()
  System.out.println("\nTesting isMemberRec()");
  System.out.println("stella is member in " + testList0.toString() + " --> " + isMemberRec("stella", testList0));
  System.out.println("stella is member in " + testList1.toString() + " --> " + isMemberRec("stella", testList1));
  System.out.println("person is member in " + testList2.toString() + " --> " + isMemberRec("person", testList2));
  System.out.println("desk is member in " + testList2.toString() + " --> " + isMemberRec("desk", testList2));
  
     //Testing isMemberWhile()
  System.out.println("\nTesting isMemberWhile()");
  System.out.println("stella is member in " + testList0.toString() + " --> " + isMemberWhile("stella", testList0));
  System.out.println("stella is member in " + testList1.toString() + " --> " + isMemberWhile("stella", testList1));
  System.out.println("person is member in " + testList2.toString() + " --> " + isMemberWhile("person", testList2));
  System.out.println("desk is member in " + testList2.toString() + " --> " + isMemberWhile("desk", testList2));
  System.out.println("I is member in " + testList8.toString() + " --> " + isMemberWhile("I", testList8));
  System.out.println("ham is member in " + testList8.toString() + " --> " + isMemberWhile("ham", testList8));
  System.out.println("after: " + testList8.toString());
     
  
  //Testing listSize()
  System.out.println("\nTesting listSize()");
  System.out.println("listSize of " + testList0.toString() + " --> " + listSize(testList0));
  System.out.println("listSize of " + testList1.toString() + " --> " + listSize(testList1));
  System.out.println("listSize of " + testList2.toString() + " --> " + listSize(testList2));
  System.out.println("listSize of " + testList8.toString() + " --> " + listSize(testList8));
  
  //Testing implodeFor()
  System.out.println("\nTesting implodeFor()");
  System.out.println("implodeFor " + testList0.toString() + " --> " + implodeFor(testList0));
  System.out.println("implodeFor " + testList1.toString() + " --> " + implodeFor(testList1));
  System.out.println("implodeFor " + testList2.toString() + " --> " + implodeFor(testList2));
  System.out.println("implodeFor " + testList8.toString() + " --> " + implodeFor(testList8));
  
  
   }
   
   //It takes a string list and returns a string that is the result of concatenating
   //all the strings in the input list in order.
   public static String implodeFor (StringList l) {
     int size = listSize(l);
     String result = "";
     for (int i =0; i < size; i=i+1) {
       result = result + head(l);
       l = tail(l);
     }
     return result;
   }

   //returns the number of elements in the input list 
   public static int listSize(StringList l) {
     int size = 0;
     while(!isEmpty(l)) {
       size = size + 1;
       l = tail(l);
     }
     return size;
   }
   
   public static boolean isMemberWhile(String s, StringList L) {
     boolean found = false;  //"found" starts out false, 
                             //and will become true when/if s is found
     String current; //"current" will hold the head of L as we walk down the list
     
     while (!isEmpty(L) && !found) {
       current = head(L);
       if (current.equals(s))  //string s was found!
         found = true;
       else 
         L = tail(L);
     }
     return found;
   }
   
   public static boolean isMemberRec(String s, StringList l) {
     if (isEmpty(l)) return false;
     if (s.equals(head(l))) return true;
     return isMemberRec(s, tail(l));
   }
   
   
 
}