需求

通用的数组类，
1、内置数据类型以及自定义数据类型进行存储
2、数组中的数据存储到堆中
3、构造函数中可以传入数组的容量
4、拷贝构造函数，operator=防止浅拷贝
5、尾插法和尾删法
6、下标访问
7、获取数组中当前元素个数和数组的容量

自定义数组类MyArray

#pragma once
#include <iostream>
using namespace std;


template <class T>
class MyArray
{
public:
	//有参构造 初始容量
	MyArray(int capacity) {
		cout << "调用MyArray有参构造" << endl;
		this->m_Capacity = capacity;
		this->m_Size = 0;
		this->pAddress = new T[this->m_Capacity];
	}
	
	//析构函数，数据释放
	~MyArray() {
		cout << "调用MyArray析构函数" << endl;
		if (this->pAddress != NULL) {
			delete[] pAddress;
			this->pAddress = NULL;
		}
	}

private:
	T * pAddress;//数组指针，用于存放数据
	int m_Size;//数组当前大小
	int m_Capacity;//容量
};

拷贝构造函数，重写operator=函数

//拷贝函数
MyArray(const MyArray& arr) {
	cout << "调用MyArray拷贝构造函数" << endl;
	this->m_Capacity = arr.m_Capacity;
	this->m_Size = arr.m_Size;
	//
	this->pAddress = new T[arr.m_Capacity];
	for (int i = 0; i < this->m_Size; i++)
	{
		this->pAddress[i] = arr.pAddress[i];
	}

}

//operator= 防止浅拷贝操作，返回自身的引用，
MyArray& operator=(const MyArray& arr)
{
	cout << "调用MyArrayoperator=函数" << endl;
	//先判断原来的堆区是否有数据，有数据释放
	if (this->pAddress != NULL)
	{
		delete[] pAddress;
		this->pAddress = NULL;
		this->m_Capacity = 0;
		this->m_Size = 0;
	}
	this->m_Capacity = arr.m_Capacity;
	this->m_Size = arr.m_Size;
	for (int i = 0; i < this->m_Size; i++)
	{
		this->pAddress[i] = arr[i];
	}
	return this;
}

尾插法和尾删法

//尾插法
void add(const T& val) {
	if (this->m_Size < this->m_Capacity)
	{

		this->pAddress[this->m_Size] = val;
		this->m_Size++;
	}
	else
	{
		//扩容
		Expansion();
		this->pAddress[this->m_Size] = val;
		this->m_Size++;
	}
}

//尾删法
void Pop_Back() {
	if (this->m_Size == 0) {
		return;
	}
	this->pAddress[m_Size - 1] = this->pAddress[m_Size];
	this->m_Size--;
}

//扩容
void Expansion() {
	T* newpAddress = new T[this->m_Capacity << 2];
	for (int i = 0; i < this->m_Size; i++)
	{
		newpAddress[i] = this->pAddress[i];
	}
	//释放原数组内存
	delete[] this->pAddress;
	//指针指向新数组
	this->pAddress = newpAddress;
	this->m_Capacity *= 2;
}

通过下标访问

//通过下标访问   &,返回可以作为左值
T& operator[](int index) {
	return this->pAddress[index];
}

获取数组大小和容量

//获取容量
int getCapacity() {
	return this->m_Capacity;
}

//获取数组大小
int getSize() {
	return this->m_Size;
}

全部代码

#pragma once
#include <iostream>
using namespace std;


template <class T>
class MyArray
{
public:
	//有参构造 初始容量
	MyArray(int capacity) {
		cout << "调用MyArray有参构造" << endl;
		this->m_Capacity = capacity;
		this->m_Size = 0;
		this->pAddress = new T[this->m_Capacity];
	}
	//拷贝函数
	MyArray(const MyArray& arr) {
		cout << "调用MyArray拷贝构造函数" << endl;
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		//
		this->pAddress = new T[arr.m_Capacity];
		for (int i = 0; i < this->m_Size; i++)
		{
			this->pAddress[i] = arr.pAddress[i];
		}

	}

	//operator= 防止浅拷贝操作，返回自身的引用，
	MyArray& operator=(const MyArray& arr)
	{
		cout << "调用MyArrayoperator=函数" << endl;
		//先判断原来的堆区是否有数据，有数据释放
		if (this->pAddress != NULL)
		{
			delete[] pAddress;
			this->pAddress = NULL;
			this->m_Capacity = 0;
			this->m_Size = 0;
		}
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		for (int i = 0; i < this->m_Size; i++)
		{
			this->pAddress[i] = arr[i];
		}
		return this;
	}

	//尾插法
	void add(const T& val) {
		if (this->m_Size < this->m_Capacity)
		{

			this->pAddress[this->m_Size] = val;
			this->m_Size++;
		}
		else
		{
			//扩容
			Expansion();
			this->pAddress[this->m_Size] = val;
			this->m_Size++;
		}
	}

	//尾删法
	void Pop_Back() {
		if (this->m_Size == 0) {
			return;
		}
		this->pAddress[m_Size - 1] = this->pAddress[m_Size];
		this->m_Size--;
	}

	//自动扩容
	void Expansion() {
		this->m_Capacity << 2;
		T* newpAddress = new T[this->m_Capacity];
		for (int i = 0; i < this->m_Size; i++)
		{
			newpAddress[i] = this->pAddress[i];
		}
		//释放原数组内存
		delete[] this->pAddress;
		//指针指向新数组
		this->pAddress = newpAddress;
		this->m_Capacity *= 2;
	}

	//获取容量
	int getCapacity() {
		return this->m_Capacity;
	}

	//获取数组大小
	int getSize() {
		return this->m_Size;
	}

	

	

	//通过下标访问   &,返回可以作为左值
	T& operator[](int index) {
		return this->pAddress[index];
	}

	



	//析构函数，数据释放
	~MyArray() {
		cout << "调用MyArray析构函数" << endl;
		if (this->pAddress != NULL) {
			delete[] pAddress;
			this->pAddress = NULL;
		}
	}

private:
	T * pAddress;//数组指针
	int m_Size;//数组大小
	int m_Capacity;//容量
};

测试代码：

```#include <iostream>
#include "MyArray.hpp"
//直接包含源文件
using namespace std;

void showArray(MyArray<int> &p) {
	for (int i = 0; i < p.getSize(); i++)
	{
		cout << p[i]<<" ";
	}
	cout<<endl;
}

class Hero
{
public:
	Hero() {};
	Hero(string name,int age) {
		this->m_Name = name;
		this->m_Age = age;
	};
	~Hero() {
	};
	string m_Name;
	int m_Age;
};

void showHeroArray(MyArray<Hero>& arr) {
	for (int i = 0; i < arr.getSize(); i++)
	{
		cout << "姓名：" << arr[i].m_Name << "   年龄：" << arr[i].m_Age << endl;
	}
}



int main() {
	MyArray<int> arr(1);
	cout << "数组容量" << arr.getCapacity() << endl;
	cout << "数组大小" << arr.getSize() << endl;
	arr.add(1);
	arr.add(2);
	arr.add(2);
	arr.add(2);
	cout << "数组容量" <<arr.getCapacity() << endl;
	cout << "数组大小" <<arr.getSize() <<endl;
	showArray(arr);
	arr.Pop_Back();
	cout << "删除尾元素" << endl;
	cout << "数组容量" << arr.getCapacity() << endl;
	cout << "数组大小" << arr.getSize() << endl;
	showArray(arr);

	MyArray<Hero> hArr(5);
	hArr.add(Hero("张三", 100));
	hArr.add(Hero("李四", 100));
	hArr.add(Hero("王五", 100));
	hArr.add(Hero("赵六", 100));
	hArr.add(Hero("田七", 100));

	showHeroArray(hArr);
	
	return 0;
}