C++函数模板和类模板——DAY7

1.类模板中的static关键字

当一个类模板中有static关键字定义的变量时，当初始化多种类型时，每种类型的类，都使用自己的变量，互不影响；但是相同类型的不同对象使用变量时会互相影响。（类模板的本质会产生相应类型的多个类）

2.综合运用：请设计一个数组模板类（MyVector），完成对int、char、Teacher类型元素的管理。

#include <iostream>
using namespace std;

template <typename T>
class MyVector
{

	friend ostream & operator<< <T>(ostream &out,  const MyVector &obj);
public:
	MyVector(int size = 0);  //构造函数
	MyVector(const MyVector &obj); // 拷贝构造函数
	~MyVector(); //析构函数

public:

	T& operator[] (int index);
	// a3 = a2 = a1;
	MyVector &operator=(const MyVector &obj);

	

public:
	int getLen()
	{
		return m_len;
	}

protected:
	T *m_space;
	int m_len;
};

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

template <typename T>
ostream & operator<<(ostream &out,  const MyVector<T> &obj)
{
	for (int i=0; i<obj.m_len; i++)
	{
		out << obj.m_space[i] << " ";
		//out << t1;
	}
	out << endl;
	return out;
}


//MyVector<int> myv1(10);
template <typename T>
MyVector<T>::MyVector(int size)  //构造函数
{
	m_space = new T[size];
	m_len = size;
}


//MyVector<int> myv2  = myv1;
template <typename T>
MyVector<T>::MyVector(const MyVector &obj) // 拷贝构造函数
{
	//根据myv1的大小分配内存
	m_len = obj.m_len;
	m_space = new T[m_len];

	//copy数据
	for (int i=0; i<m_len; i++)
	{
		m_space[i] = obj.m_space[i];
	}

}

template <typename T>
MyVector<T>::~MyVector() //析构函数
{
	if (m_space != NULL)
	{
		delete [] m_space;
		m_space = NULL;
		m_len = 0;
	}
}

template <typename T>
T& MyVector<T>::operator[] (int index)
{
	return m_space[index];
}


// a3 = a2 = a1;
template <typename T>
MyVector<T> &  MyVector<T>::operator=(const MyVector<T> &obj)
{
	//先把a2的旧的内存释放掉

	if (m_space != NULL)
	{
		delete[] m_space;
		m_space = NULL;
		m_len = 0;
	}

	//根据a1分配内存 
	m_len = obj.m_len;
	m_space = new T[m_len];

	//copy数据
	for (int i=0; i<m_len; i++)
	{
		m_space[i] = obj[i];
	}
	return *this;  // a2 = a1; 返回给a2 的自身
}

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;

#include "MyVector.cpp"

//1  优化Teacher类, 属性变成 char *panme, 购置函数里面 分配内存
//2  优化Teacher类,析构函数 释放panme指向的内存空间
//3  优化Teacher类,避免浅拷贝 重载= 重写拷贝构造函数 
//4  优化Teacher类,在Teacher增加 << 
//5  在模板数组类中,存int char Teacher Teacher*(指针类型)

//=====>stl 容器的概念 


class Teacher
{
public:
	Teacher()
	{
		age = 33;
		strcpy(name, "");
	}

	Teacher(char *name, int age)
	{
		this->age = age;
		strcpy(this->name, name);
	}
	void printT()
	{
		cout << name << ", " << age << endl;
	}
private:
	int age;
	//char name[32];
	char *pName2;
};


void main()
{
	Teacher t1("t1", 31), t2("t2", 32), t3("t3", 33), t4("t4", 34);

	MyVector<Teacher> tArray(4);

	tArray[0] = t1;
	tArray[1] = t2;
	tArray[2] = t3;
	tArray[3] = t4;

	for (int i=0; i<4; i++)
	{
		Teacher tmp = tArray[i];
		tmp.printT();
	}
	cout << tArray;



	system("pause");
}
void main02()
{
	MyVector<char> myv1(10);
	myv1[0] = 'a';
	myv1[1] = 'b';
	myv1[2] = 'c';
	myv1[3] = 'd';

	cout << myv1;

	system("pause");
}

void main01()
{
	MyVector<int> myv1(10);

	for (int i=0; i<myv1.getLen(); i++)
	{
		myv1[i] = i+1;
		cout << myv1[i] << " ";
	}
	cout << endl;


	MyVector<int> myv2  = myv1;
	for (int i=0; i<myv2.getLen(); i++)
	{
		cout << myv2[i] << " ";
	}

	cout << myv2 << endl;
	
	cout<<"hello..."<<endl;
	system("pause");
	return ;
}