␡
- The Takeaway
- Document Management
- The Base Class: AnyOldDocument
- Economy in Coding
- The First Document Type: A Memo
- The Second Document Typean Invoice
- The Third and Last Document Typea Contract
- Leveraging Base Class Generality
- Polymorphism
- Complete Program Output
- Make Your Destructors Virtual
- Conclusion
- Additional Reading
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The Third and Last Document Type—a Contract
I want to introduce one more document type—this time a contract illustrated in Listing 6.
Listing 6 Contract Document
class ContractDocument : AnyOldDocument {
public:
explicit ContractDocument(int Id, char* name, int docType, int number);
virtual ~ContractDocument();
const int getPenaltyClauseValue();
void setPenaltyClauseValue(int number);
};
ContractDocument::ContractDocument(int Id, char* name, int docType, int number)
: AnyOldDocument(Id, name, docType, number)
{
printf ("Creating a contract document for: %s\n", name);
}
ContractDocument::~ContractDocument() { }
const int ContractDocument::getPenaltyClauseValue()
{
return GetAssociatedNumber();
}
void ContractDocument::setPenaltyClauseValue(int number)
{
SetAssociatedNumber(number);
}
Listing 6 is pretty similar to the InvoiceDocument class. The main difference between these two classes is in semantics relating to our old friend: the base class data member called associatedNumber. In the case of InvoiceDocument, this data element represents a price, whereas in the case of the contract class, the associatedNumber element represents a penalty clause value. Penalty clauses are sometimes attached to contracts to act as an incentive for a contractor to complete the work.