1: // Created by Frank M. Carrano and Timothy M. Henry.
2: // Copyright (c) 2017 Pearson Education, Hoboken, New Jersey.
4: template <class KeyType, class ValueType>
5: bool ArrayDictionary<KeyType, ValueType>::add(const KeyType& searchKey,
6: const ValueType& newValue)
7: throw(PrecondViolatedExcept)
8: {
9: bool ableToInsert = (itemCount < maxItems);
10: if (ableToInsert)
11: {
12: // Make room for new entry by shifting all entries at
13: // positions >= newPosition toward the end of the array
14: // (no shift if newPosition == itemCount + 1). Performing
15: // a binary search doesn't help here, because we need to
16: // shift the entries while looking for the location of the addition.
17: int index = itemCount;
18:
19: // Short-circuit evaluation is important
20: while ( (index > 0) && (searchKey < items[index – 1].getKey()) )
21: {
22: items[index] = items[index–1];
23: index--;
24: } // end while
25:
26: // Enforce precondition: Ensure distinct search keys
27: if (searchKey != items[index – 1].getKey())
28: {
29: // Insert new entry
30: items[index] = Entry<KeyType, ValueType>(searchKey, newValue);
31: itemCount++; // Increase count of entries
32: }
33: else
34: {
35: auto message = "Attempt to add an entry whose search key exists in dictionary.";
36: throw(PrecondViolatedExcept(message));
37: } // end if
38: } // end if
39:
40: return ableToInsert;
41: } // end add