list2004.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&);

    class xBoundary {};  // define the exception class

  private:
    int *pType;
    int  itsSize;
};

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

Array& Array::operator=(const Array &rhs)
{
   if (this == &rhs)
      return *this;
   delete [] pType;
   itsSize = rhs.GetitsSize();
   pType = new int[itsSize];
   for (int i = 0; i < itsSize; i++)
   {
      pType[i] = rhs[i];
   }
   return *this;
}

Array::Array(const Array &rhs)
{
   itsSize = rhs.GetitsSize();
   pType = new int[itsSize];
   for (int i = 0; i < itsSize; i++)
   {
      pType[i] = rhs[i];
   }
}

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

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

ostream& operator<< (ostream& output, const Array& theArray)
{
   for (int i = 0; i<theArray.GetitsSize(); i++)
      output << "[" << i << "] " << theArray[i] << endl;
   return output;
}

int main()
{
   Array intArray(20);
   try
   {
      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;
  }
  cout << "Done." << endl;
  return 0;
}