C++大学基础教程_11_8_实例研究:Array类

//Array.h

#ifndef ARRAY_H_
#define ARRAY_H_
#include <iostream>
using namespace std;

class Array
{
	//友元函数---同时也是重载运算符函数
	friend ostream &operator<<(ostream &,const Array &);
	friend istream &operator>>(istream&,Array &);
public:
	Array(int = 10);//构造函数
	Array(const Array &);//拷贝构造函数
	~Array();//析构函数
	int getSize() const;
	const Array &operator=(const Array &);//重载=
	bool operator==(const Array &) const;//重载==
	bool operator!=(const Array &right) const
	{
		return !(*this == right);//重载！=，利用重载的==函数
	}
	int &operator[](int);//重载[]适用于不是const的对象
	int operator[](int) const;//适用于const对象
private:
	int size;//存放数组的元素个数
	int *Ptr;//指向每个数组第元素的指针
};

#endif

//Array.cpp

#include <iostream>
#include <iomanip>
#include <cstdlib>
using namespace std;
#include "Array.h"

//友元重载操作符'<<'函数
//注意输出操作符是output
ostream &operator<<(ostream &output,const Array &testArray)
{
	int i;
	for(i=0;i<testArray.size;i++)
	{
		output << setw(12) << testArray.Ptr[i];
		if((i+1)%4 == 0)//换行
			output << endl;
	}
	if(i%4 != 0)
		output << endl;
	return output;
}

//友元重载操作符'>>'函数
//注意输出操作符是input
istream &operator>>(istream &input,Array &testArray)
{
	for(int i=0;i<testArray.size;i++)
		input >> testArray.Ptr[i];
	return input;
}

Array::Array(int arraySize)
{
	size = (arraySize>0 ? arraySize:10);/*错把两个arraySize写成size！！，蛋疼的错误
	                                                         前后arraySize不一致，试试看咯，简直掉渣天*/
	Ptr = new int[size];
	for(int i=0;i<size;i++)//给数组元素全部赋值为0
		Ptr[i] = 0;
}

//拷贝构造函数
Array::Array(const Array &arrryToCopy)
	:size(arrryToCopy.size)
{
	Ptr = new int[size];
	for(int i=0;i<size;i++)
		Ptr[i] = arrryToCopy.Ptr[i];
}

Array::~Array()
{
	delete [] Ptr;
	Ptr = 0;
}

int Array::getSize() const
{
	return size;
}

//重载=
const Array &Array::operator=(const Array &testArray)
{
	if(this->Ptr != testArray.Ptr)//避免自我复制，赋值
	{
		if(size != testArray.size)
		{
			size = testArray.size;
			delete [] Ptr;
			Ptr = new int[testArray.size];
			for(int i=0;i<size;i++)
				Ptr[i] = testArray.Ptr[i];
		}
	}
	return *this;
}

//重载==
bool Array::operator==(const Array &testArray) const
{
	if(this->size != testArray.size)
		return false;
	for(int i=0;i<testArray.size;i++)
		if(this->Ptr[i] != testArray.Ptr[i])
			return false;
	return true;
}

//重载[]，适用不是const的对象
int &Array::operator[](int number)
{
	if((number<0)||(number>=this->size))
		cout << "\nError:number " << number 
		       << "out of range." << endl;
	return this->Ptr[number];
}

int Array::operator[](int number) const
{
	if((number<0)||(number>=this->size))
		cout << "\nError:number " << number 
		       << "out of range." << endl;
	return this->Ptr[number];
}

//main.cpp

#include "Array.h"
#include <iostream>
using namespace std;

int main()
{
	Array integers1(7);
	Array integers2;
	cout << "Size of integers1 is " << integers1.getSize()
		   << "\nArray after initialization:\n"  
		   << integers1 << endl;//调用重载运算符函数<<
	cout << "Size of integers2 is " << integers2.getSize()
		   << "\nArray after initialization:\n" 
		   << integers2 ;//调用重载运算符函数<<
	cout << "Enter 17integers:"<< endl;
	cin >> integers1 >> integers2;//调用重载运算符函数>>
	cout << "\nAfter input ,the array contains:\n" 
		   << "Integers1:\n" << integers1
		   << "Integers2:\n" << integers2;
	cout << "\nEvaluating: integers1!=integers2" << endl;
	if(integers1 != integers2)
		cout << "integers1 and integers2 are not equal." << endl;
	
	Array integers3(integers1);//拷贝构造函数
    cout << "Size of integers3 is " << integers3.getSize()
		   << "\nArray after initialization:\n"  
		   << integers3 << endl;//调用重载运算符函数<<

	cout << "Assigning integers2 to integers1:" << endl;
	integers1 = integers2;//调用重载运算符函数=
	cout << "integer1:\n" << integers1
		   << "\ninteger2:\n" << integers2;

	cout << "Evaluating : integers1==integers2 :" << endl;
	if(integers1 == integers2)//调用重载运算符函数==
		cout << "integers1 and integers2 are equal." << endl;

	cout << "integers1[5] is " << integers1[5] << endl;//调用重载运算符函数[] 
	cout << "Assigning 1000 to integers1[5]" << endl;
	integers1[5] = 1000;
	cout << "integers1:\n" << integers1 << endl;
	cout << "Attempt to assign 1000 to integers1[15]" << endl;
	integers1[15] = 1000; 

	system("pause >> cout");
	return 0;
}