BACKGROUND INFORMATION

The Bibliography Abstract Data Type stores references. References can be added to the bibliography or removed from the bibliography. No matter how references are represented, they are ordered. Duplicate references are not allowed. You can assume that each author has just one publication and that each publication has only one author.

The ADT for a Bibliography includes these operations:

• new, which creates a new, empty bibliography
• addReference, which adds a reference to the bibliography
• removeReference, which removes a reference from the bibliography
• outputBibliography, which generates an ordered list of references

QUESTION

Suppose a reference is represented by a list of three strings: the author, the year and the title, e.g. ['Harris, R', '1995', 'Enigma']

--------------------

(1) Specify the problem of retrieving the author from a reference by completing the following template. You may write the specification in English and/or formally with mathematical notation.

--------------------

(2) Give your initial insight for an algorithm that creates a list of all the authors of references in a given bibliography. You must use at least one of the Bibliography ADTs operations. You may assume that you have a retrieveAuthor operation that solves the computational problem specified in part (i). You can also use any of the basic list operations: create an empty list, append an item, calculate the length, access an item by position (indexing), iterate over the items or over the indices, check if two lists are equal.

--------------------

Holden, G Cripps, s Xavier, 1 Brown, D Ferret, Hominid, P Krowley, J Name: retrieveAuthor Inputs: Preconditions: Outputs: Postconditions: Holden, G Cripps, s Xavier, 1 Brown, D Ferret, Hominid, P Krowley, J Name: retrieveAuthor Inputs: Preconditions: Outputs: Postconditions