泛型编程——类模板案例

原创已于 2023-04-16 16:45:24 修改 · 192 阅读

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于 2023-04-15 23:18:40 首次发布

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文章展示了如何使用C++实现一个名为MyArray的动态数组类，包括有参构造、拷贝构造（深拷贝）、赋值运算符重载（防止浅拷贝）、析构函数。此外，还实现了尾插法Push_Back、尾删法Pop_Back以及访问元素、获取容量和大小的方法。文章通过测试用例演示了类的功能，包括插入整数和自定义Person对象到数组中。

需求分析：

1、数组初始化，构造，拷贝（深），析构

MyArray.hpp

#pragma once
#include<iostream>
using namespace std;
template<class T>
class MyArray
{
public:
	//有参构造 参数 容量
	MyArray(int capacity)
	{
		cout << "MyArray的有参构造调用" << endl;
		this->m_Capacity = capacity;
		this->m_Size = 0;
		this->pAddress = new T[this->m_Capacity];
	}
	//拷贝构造函数
	MyArray(const MyArray& arr)
	{
		cout << "MyArray的拷贝构造调用" << endl;
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		this->pAddress = new T[arr.m_Capacity];//深拷贝
		//如果原来就有数据量，将arr中的数据都拷贝过来
		for (int i = 0; i < this->m_Size; i++)
		{
			this->pAddress[i] = arr.pAddress[i];
		}
	}
	//operator=防止浅拷贝的问题
	MyArray& operator=(const MyArray& arr)
	{
		cout << "MyArray的operator=调用" << endl;
		//先判断原来堆区是否有数据
		if (this->pAddress != NULL)
		{
			delete[]this->pAddress;
			this->pAddress = NULL;
			this->m_Capacity = 0;
			this->m_Size = 0;
		}
		//深拷贝
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		this->pAddress = new T[arr.m_Capacity];
		//如果原来就有数据量，将arr中的数据都拷贝过来
		for (int i=0;i<this->m_Size;i++)
		{
			this->pAddress[i] = arr.pAddress[i];
		}
		return *this;
	}
	//析构函数
	~MyArray()
	{
		if (this->pAddress != NULL)
		{
			cout << "MyArray的析构函数调用" << endl;
			delete[]pAddress;
			pAddress = NULL;
		}
	}
private:
	T* pAddress;//指针指向堆区开辟的数组
	int m_Capacity;//数组容量
	int m_Size;//数组太小
};

实现测试：

#include<iostream>
using namespace std;
#include"MyArray.hpp"
void test01()
{
	MyArray<int>arr1(5);
	MyArray<int>arr2(arr1);
	MyArray<int>arr3(100);
	arr3 = arr1;
}
int main()
{
	test01();
	system("pause");
	return 0;
}

结果：

2、尾插法，尾删法插入或删除数组中元素；获取容量，大小，更新大小；测试插入自定义数据类型

MyArray.hpp

#pragma once
#include<iostream>
using namespace std;
template<class T>
class MyArray
{
public:
	//有参构造 参数 容量
	MyArray(int capacity)
	{
		cout << "MyArray的有参构造调用" << endl;
		this->m_Capacity = capacity;
		this->m_Size = 0;
		this->pAddress = new T[this->m_Capacity];
	}
	//拷贝构造函数
	MyArray(const MyArray& arr)
	{
		cout << "MyArray的拷贝构造调用" << endl;
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		this->pAddress = new T[arr.m_Capacity];//深拷贝
		//如果原来就有数据量，将arr中的数据都拷贝过来
		for (int i = 0; i < this->m_Size; i++)
		{
			this->pAddress[i] = arr.pAddress[i];
		}
	}
	//operator=防止浅拷贝的问题
	MyArray& operator=(const MyArray& arr)
	{
		cout << "MyArray的operator=调用" << endl;
		//先判断原来堆区是否有数据
		if (this->pAddress != NULL)
		{
			delete[]this->pAddress;
			this->pAddress = NULL;
			this->m_Capacity = 0;
			this->m_Size = 0;
		}
		//深拷贝
		this->m_Capacity = arr.m_Capacity;
		this->m_Size = arr.m_Size;
		this->pAddress = new T[arr.m_Capacity];
		//如果原来就有数据量，将arr中的数据都拷贝过来
		for (int i=0;i<this->m_Size;i++)
		{
			this->pAddress[i] = arr.pAddress[i];
		}
		return *this;
	}
	//尾插法
	void Push_Back(const T& val)
	{
		//判断容量是否等于大小
		if (this->m_Capacity == this->m_Size)
		{
			return;
		}
		this->pAddress[this->m_Size] = val;//在数组的末尾插入数据
		this->m_Size++;//更新数组的大小
	}
	//尾删法
	void Pop_Back()
	{
		//让用户访问不到最后一个元素，即尾删，逻辑删除
		if (this->m_Size == 0)
		{
			return;
		}
		this->m_Size--;
	}
	//通过下标的方式访问数组中的元素
	T& operator[](int index)
	{
		return this->pAddress[index];
	}
	//返回数组容量
	int getCapacity()
	{
		return this->m_Capacity;
	}
	//返回数组大小
	int getSize()
	{
		return this->m_Size;
	}
	//析构函数
	~MyArray()
	{
		if (this->pAddress != NULL)
		{
			cout << "MyArray的析构函数调用" << endl;
			delete[]pAddress;
			pAddress = NULL;
		}
	}
private:
	T* pAddress;//指针指向堆区开辟的数组
	int m_Capacity;//数组容量
	int m_Size;//数组太小
};

测试：

#include<iostream>
using namespace std;
#include"MyArray.hpp"
void printIntArray(MyArray<int>&arr)
{
	for (int i = 0; i < arr.getSize(); i++)
	{
		cout << arr[i] << " ";//由于前面重载了[]
	}
	cout << endl;
}
void test01()
{
	MyArray<int>arr1(5);
	for (int i = 0; i < 5; i++)
	{
		//利用尾插法向数组中插入数据
		arr1.Push_Back(i);
	}
	printIntArray(arr1);
	cout << "arr1的容量为：" << arr1.getCapacity() << endl;
	cout << "arr1的大小为：" << arr1.getSize() << endl;
	MyArray<int>arr2(arr1);
	printIntArray(arr2);
	//尾删
	arr2.Pop_Back();
	cout << "arr2尾删后：" << endl;
	cout << "arr2的容量为：" << arr2.getCapacity() << endl;
	cout << "arr2的大小为：" << arr2.getSize() << endl;
	MyArray<int>arr3(100);
	arr3 = arr1;
}
//测试自定义数据类型
class Person
{
public:
	Person() {};
	Person(string name, int age)
	{
		m_Name = name;
		m_Age = age;
	}
	string m_Name;
	int m_Age;
};
void printPersonArray(MyArray<Person>&arr)
{
	for (int i = 0; i < arr.getSize(); i++)
	{
		cout << "姓名：" << arr[i].m_Name << " " << "年龄：" << arr[i].m_Age << endl;
	}
}
void test02()//测试数组中存放person数据类型
{
	MyArray<Person>arr(10);
	Person p1("孙悟空", 999);
	Person p2("韩信", 30);
	Person p3("妲己", 20);
	Person p4("赵云", 25);
	Person p5("安琪拉", 27);
	//将数据插入到数组中
	arr.Push_Back(p1);
	arr.Push_Back(p2);
	arr.Push_Back(p3);
	arr.Push_Back(p4);
	arr.Push_Back(p5);
	//打印数组
	printPersonArray(arr);
	//输出容量
	cout << "arr容量为：" << arr.getCapacity() << endl;
	cout << "arr大小为：" << arr.getSize() << endl;
}
int main()
{
	//test01();
	test02();
	system("pause");
	return 0;
}