/* Dictionary.h
   Specification of a Dictionary Class
   [Taken from requirements found at
    http://ciips.ee.uwa.edu.au/~morris/clp110/examp_req.html.]
   Author: J Morris
   Date Last Modified: 2 October, 1997
*/

typedef struct dictionary *Dictionary;

Dictionary ConsDictionary( int max_words );
/* Construct a new dictionary.
   Pre-cond: max_words > 0
   Post-cond: returns a newly constructed Dictionary 
               or
              NULL if insufficient memory
*/

int DeleteDictionary( Dictionary d );
/* Delete a dictionary.
   Pre-cond: d is a valid Dictionary
   Post-cond: space used by d has been freed
              returns TRUE if no errors, FALSE on error
*/

int WordCount( Dictionary d );
/* Count words in the dictionary
   Pre-cond: d is a valid Dictionary
   Post-cond: returns count of words currently in Dictionary
*/

int AddTranslation( Dictionary d, char *lang1, char *lang2 );
/* Add a new translation to the dictionary
   Neither lang1 nor lang2 may be in the dictionary already
   Pre-cond: d is a valid Dictionary and
             lang1 != NULL and strlen( lang1 ) > 0 and
             lang2 != NULL and strlen( lang2 ) > 0 and
             FindForeign( d, lang1 ) == NULL and
             FindEnglish( d, lang2 ) == NULL
   Post-cond: WordCount( d ) = old WordCount( d ) + 1 and
              strcmp( FindForeign( d, lang1 ), lang2 ) == 0 and
              strcmp( FindEnglish( d, lang2 ), lang1 ) == 0 
*/
   
int ReplaceTranslation( Dictionary d, char *lang1, char *lang2 );
/* Replace an existing translation in the dictionary
   lang1 must be in the dictionary already
   lang2 must not be in the dictionary already
   Pre-cond: d is a valid Dictionary and
             lang1 != NULL and strlen( lang1 ) > 0 and
             lang2 != NULL and strlen( lang2 ) > 0 and
             FindForeign( d, lang1 ) != NULL and
             FindEnglish( d, lang2 ) == NULL
   Post-cond: WordCount( d ) = old WordCount( d ) + 1 and
              strcmp( FindForeign( d, lang1 ), lang2 ) == 0 and
              strcmp( FindEnglish( d, lang2 ), lang1 ) == 0 
*/

char *FindForeign( Dictionary d, char *word );
char *FindEnglish( Dictionary d, char *word );
/* Find translations
   Pre-cond: d is a valid Dictionary
             word != NULL and strlen( word ) > 0 
   Post-cond: returns the translation string or
              NULL if word is not in the dictionary
*/