4elist2002.cpp

《21天学通C＋＋》附盘的原代码。书上的每个例子在这里都有相应的C语言程序。

#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 xTooBig {};
	class xTooSmall{};
	class xZero {};
	class xNegative {};
private:
	int *pType;
	int  itsSize;
};

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


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

	return pType[0];  // appease MFC
}


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

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

int main()
{
	try
	{
		Array intArray(0);
		for (int j = 0; j< 100; j++)
		{
			intArray[j] = j;
			cout << "intArray[" << j << "] okay...\n";
		}
	}
	catch (Array::xBoundary)
	{
		cout << "Unable to process your input!\n";
	}
	catch (Array::xTooBig)
	{
		cout << "This array is too big...\n";
	}
	catch (Array::xTooSmall)
	{
		cout << "This array is too small...\n";
	}
	catch (Array::xZero)
	{
		cout << "You asked for an array";
		cout << " of zero objects!\n";
	}
	catch (...)
	{
		cout << "Something went wrong!\n";
	}
	cout << "Done.\n";
	return 0;
}