method clear simply re-initializes the dictionary the remove method is similar to findexcept that it also deletes the record returned from the dictionary once againif there are multiple records in the dictionary that match the desired keythere is no requirement as to which one actually is removed and returned method size returns the number of elements in the dictionary the remaining method is removeany this is similar to removeexcept that it does not take key value insteadit removes an arbitrary record from the dictionaryif one exists the purpose of this method is to allow user the ability to iterate over all elements in the dictionary (of coursethe dictionary will become empty in the processwithout the removeany methoda dictionary user could not get at record of the dictionary that he didn' already know the key value for with the removeany methodthe user can process all records in the dictionary as shown in the following code fragment while (dict size( it dict removeany()dosomething(it)there are other approaches that might seem more natural for iterating though dictionarysuch as using "firstand "nextfunction but not all data structures that we want to use to implement dictionary are able to do "firstefficiently for examplea hash table implementation cannot efficiently locate the record in the table with the smallest key value by using removeanywe have mechanism that provides generic access given database storing records of particular typewe might want to search for records in multiple ways for examplewe might want to store payroll records in one dictionary that allows us to search by idand also store those same records in second dictionary that allows us to search by name figure shows the definition for payroll record the payroll class has multiple fieldseach of which might be used as search key simply by varying the type for the keyand looking at the appropriate field in each recordwe can define dictionary whose search key is the id fieldanother whose search key is the name fieldand third whose search key is the address field of the payroll class figure shows an example where payroll objects are stored in two separate dictionariesone using the id field as the key and the other using the name field as the key the fundamental operation for dictionary is finding record that matches given key this raises the issue of how to extract the key from record we would like any given dictionary implementation to support arbitrary record typesso we