list2007.cpp

teach yourself C++ in 21 days 第五版

#include <iostream>
using namespace std;

const int DefaultSize = 10;

class Array
{
  public:
    // constructors
    Array(int itsSize = DefaultSize);
    Array(const Array &rhs);
    ~Array() { delete [] pType;}

    // operators
    Array& operator=(const Array&);
    int& operator[](int offSet);
    const int& operator[](int offSet) const;
 
    // accessors
    int GetitsSize() const { return itsSize; }

    // friend function
    friend ostream& operator<< (ostream&, const Array&);
 
    // define the exception classes
    class xBoundary {};
    class xSize
    {
      public:
        xSize(int size):itsSize(size) {}
        ~xSize(){}
        int GetSize() { return itsSize; }
     private:
        int itsSize;
    };
 
    class xTooBig : public xSize
    {
      public:
        xTooBig(int size):xSize(size){}
    };
 
    class xTooSmall : public xSize
    {
      public:
        xTooSmall(int size):xSize(size){}
    };
 
    class xZero  : public xTooSmall
    {
      public:
        xZero(int size):xTooSmall(size){}
    };

    class xNegative : public xSize
    {
      public:
        xNegative(int size):xSize(size){}
    };

  private:
    int *pType;
    int  itsSize;
};


Array::Array(int size):
itsSize(size)
{
   if (size == 0)
      throw xZero(size);
   if (size > 30000)
      throw xTooBig(size);
   if (size < 1)
      throw xNegative(size);
   if (size < 10)
      throw xTooSmall(size);

   pType = new int[size];
   for (int i = 0; i < size; i++)
      pType[i] = 0;
}


int& Array::operator[] (int offSet)
{
   int size = GetitsSize();
   if (offSet >= 0 && offSet < size)
      return pType[offSet];
   throw xBoundary();
   return pType[0];
}

const int& Array::operator[] (int offSet) const
{
   int size = GetitsSize();
   if (offSet >= 0 && offSet < size)
      return pType[offSet];
   throw xBoundary();
   return pType[0];
}

int main()
{
   try
   {
      Array intArray(9);
      for (int j = 0; j < 100; j++)
      {
         intArray[j] = j;
         cout << "intArray[" << j << "] okay..." << endl;
      }
   }
   catch (Array::xBoundary)
   {
      cout << "Unable to process your input!" << endl;
   }
   catch (Array::xZero theException)
   {
      cout << "You asked for an Array of zero objects!" << endl;
      cout << "Received " << theException.GetSize() << endl;
   }
   catch (Array::xTooBig theException)
   {
      cout << "This Array is too big..." << endl;
      cout << "Received " << theException.GetSize() << endl;
   }
   catch (Array::xTooSmall theException)
   {
      cout << "This Array is too small..." << endl;
      cout << "Received " << theException.GetSize() << endl;
   }
   catch (...)
   {
      cout << "Something went wrong, but I've no idea what!\n";
   }
   cout << "Done." << endl;
   return 0;
}