External Interfaces/API

Description of Function pb_change

1. Find the Entry to Change, and Confirm

Arguments passed to pb_change are the Properties object pb_htable and the name key for the requested entry. The pb_change function calls get on pb_htable with the name key, on which pb_keyfilter is called to change spaces to underscores. The get method returns the entry (or null, if the entry is not found) to variable entry. pb_change calls isempty to determine whether the entry is empty. If the entry is empty, pb_change displays a message that the name will be added to the phone book, and allows the user to enter the phone number(s) for the entry.

If the entry is found, in the else clause, pb_change calls pb_display to display the entry. It then uses input to ask the user to confirm the replacement. If the user enters anything other than y, the function returns.

• function pb_change(pb_htable,name)
  entry = pb_htable.get(pb_keyfilter(name));
  if isempty(entry)
     disp(sprintf('The name %s is not in the phone book', name));
     return;
  else
     pb_display(entry);
     r = input('Replace phone numbers in this entry (y/n)? ','s');
     if r ~= 'y'
        return;
     end;
  end;
  

2. Input New Phone Number(s) and Change the Phone Book Entry

pb_change uses disp to display a prompt for new phone number(s). Then, pb_change inputs data into variable entry, with the same statements described in 1. Input the Entry to Add.

Then, to replace the existing entry with the new one, pb_change calls put on pb_htable with the (filtered) key name and the new entry. It then displays a message that the entry has been changed.

• disp 'Type in the new phone number(s), one per line.'
  disp 'To complete the entry, type an extra Enter.'
  disp(sprintf(':: %s', name));
  entry=[name '^'];
  while 1
     line = input(':: ','s');
     if isempty(line)
        break;
     else
        entry=[entry line '^'];
     end;
  end;
  pb_htable.put(pb_keyfilter(name),entry);
  disp ' '
  disp(sprintf('The entry for %s has been changed', name));
  

Description of Function pb_remove

Description of Function pb_listall