Sams Teach Yourself C++ in 21 Days

Answers 871

D

72: cout << “Enter an int: “;

73: cin >> testNumber;

74:

75: // this weird test should be replaced by a series

76: // of tests to complain about bad user input

77:

78: if (testNumber > 3768 || testNumber < 0)

79: throw RangeError(testNumber);

80:

81: *myInt = testNumber;

82: cout << “Ok. myInt: “ << *myInt;

83: delete myInt;

84: }

4. The following is one possible answer:
   0: // Exercise 20.4
   1: #include
   2: using namespace std;
   3: // Abstract exception data type
   4: class Exception
   5: {
   6: public:
   7: Exception(){}
   8: virtual ~Exception(){}
   9: virtual void PrintError() = 0;
   10: };
   11:
   12: // Derived class to handle memory problems.
   13: // Note no allocation of memory in this class!
   14: class OutOfMemory : public Exception
   15: {
   16: public:
   17: OutOfMemory(){}
   18: ~OutOfMemory(){}
   19: virtual void PrintError();
   20: private:
   21: };
   22:
   23: void OutOfMemory::PrintError()
   24: {
   25: cout << “Out of Memory!!\n”;
   26: }
   27:
   28: // Derived class to handle bad numbers
   29: class RangeError : public Exception
   30: {
   31: public:
   32: RangeError(unsigned long number){badNumber = number;}
   33: ~RangeError(){}
   34: virtual void PrintError();
   35: virtual unsigned long GetNumber() { return badNumber; }

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