/**

* Checks whether a Queue contains a particular entry

*

* @param x

* the entry to be found

* @return true if the entry was found in this

*/

public boolean contains(T x) { ... }

/**

* Checks whether a Sequence of NaturalNumbers is a palindrome.

* i.e. can be read the same forwards and backwards.

*

* @param sn

* Sequence to be checked

* @return true if sn is a palindrome, false otherwise

* @ensures isPalindrome = (sn = rev(sn))

*/

private static boolean isPalindrome(Sequence sn) {...}

/**

* Checks whether a Stack of Integers is a palindrome.

* i.e. can be read the same forwards and backwards.

*

* @param si

* Stack to be checked

* @return true if si is a palindrome, false otherwise

* @ensures isPalindrome = (si = rev(si))

*/

private static boolean isPalindrome(Stack si) {...}

/**

* Checks whether a Queue is a palindrome.

* i.e. can be read the same forwards and backwards.

*

* @return true if this is a palindrome, false otherwise

* @ensures isPalindrome = (this = rev(this))

*/

private boolean isPalindrome() {...}