doc/docs/CPlusPlus-main/24_C++的类中运算符重载.ipynb
sairate fa9377e4ae docs(book): 添加现代 C++教程及相关代码
- 新增现代 C++ 教程的 Preface 章节,包括英文和中文版本
- 添加 C++ Primer 练习代码
- 新增 Learn C++ 教程的 C++ 开发简介章节
- 添加头文件解析文档
- 更新 mkdocs.yml,包含新教程的目录结构
- 修改项目设置,使用 Python 3.10环境
2025-07-08 09:52:45 +08:00

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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# C++ 运算符重载"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 1. 运算符重载简介"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① 运算符重载:对已有的运算符重新进行定义,赋予其另一种功能,以适应不同的数据类型。\n",
"\n",
"② 对于内置的数据类型的表达式的运算符是不可能改变的。"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 2. 加号运算符重载"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① 加号运算符作用:实现两个自定义数据类型相加的运算。"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"\n",
"//加号运算符重载\n",
"class Person\n",
"{\n",
"public:\n",
"\n",
" //1、成员函数重载+号\n",
" Person operator+(Person& p)\n",
" {\n",
" Person temp;\n",
" temp.m_A = this->m_A + p.m_A;\n",
" temp.m_B = this->m_B + p.m_B;\n",
" return temp;\n",
" }\n",
" int m_A;\n",
" int m_B;\n",
"};\n",
"\n",
"/*\n",
"//全局函数重载+号\n",
"Person operator+(Person &p1, Person &p2)\n",
"{\n",
" Person temp;\n",
" temp.m_A = p1.m_A + p2.m_A;\n",
" temp.m_B = p1.m_B + p2.m_B;\n",
" return temp;\n",
"}\n",
"*/\n",
"\n",
"//函数重载的版本\n",
"Person operator+(Person& p1, int num)\n",
"{\n",
" Person temp;\n",
" temp.m_A = p1.m_A + num;\n",
" temp.m_B = p1.m_B + num;\n",
" return temp;\n",
"}\n",
"\n",
"void test01()\n",
"{\n",
" Person p1;\n",
" p1.m_A = 10;\n",
" p1.m_B = 10;\n",
" Person p2;\n",
" p2.m_A = 10;\n",
" p2.m_B = 10;\n",
"\n",
" //成员函数重载本质调用 \n",
" //Person p3 = p1.operator+(p2);\n",
" \n",
" //全局函数重载本质调用 \n",
" //Person p3 = operator+(p1,p2);\n",
" \n",
" Person p3 = p1 + p2; //重载本质被简化后的形式\n",
"\n",
" //运算符重载,也可以发生函数重载\n",
"\n",
" Person p4 = p1 + 10; //Person + int\n",
"\n",
" cout << \"p3.m_A\" << p3.m_A << endl;\n",
" cout << \"p3.m_B\" << p3.m_B << endl;\n",
"\n",
" cout << \"p4.m_A\" << p4.m_A << endl;\n",
" cout << \"p4.m_B\" << p4.m_B << endl;\n",
"\n",
"}\n",
"\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
"\n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - p3.m_A20 \n",
" - p3.m_B20 \n",
" - p4.m_A20 \n",
" - p4.m_B20 \n",
" - 请按任意键继续. . ."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 3. 左移运算符重载"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① 左移运算符重载:可以输出自定义数据类型。\n",
"\n",
"② 重载左移运算符配合友元可以实现自定义数据类型。"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"\n",
"//左移运算符\n",
"class Person\n",
"{\n",
"\n",
" friend ostream& operator<<(ostream& out, Person& p);\t\n",
"\n",
"public:\n",
" Person(int a, int b)\n",
" {\n",
" m_A = a;\n",
" m_B = b;\n",
" }\n",
"\n",
" /*\n",
" //利用成员函数重载 左移运算符 p.operator<<(cout) 简化版本 p << cout\n",
" //成员函数不能利用重载<<运算符因为无法实现cout在左侧\n",
" //当不知道返回值是什么类型的时候可以先写个void以后再改\n",
" void operator<<(Person& p)\n",
" {\n",
" \n",
" }\n",
" */\n",
" \n",
"private:\n",
" int m_A;\n",
" int m_B;\n",
"};\n",
"\n",
"//只能利用全局函数重载左移运算符\n",
"//如果返回类型为void那么就无法无限追加也没有办法在后面添加换行符\n",
"ostream & operator<<(ostream &cout, Person &p) //本质 operator << (cout , p) , 简化 cout << p\n",
" //cout是别名这里可以取out、kn...\n",
" //cout为ostream输出流数据类型 \n",
"{\n",
" cout << \"m_A= \" << p.m_A << \" m_B=\" << p.m_B;\n",
" return cout;\n",
"}\n",
"\n",
"void test01()\n",
"{\n",
" Person p(10,10);\n",
"\n",
" cout << p << \" hello world\" << endl;\n",
"}\n",
"\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
"\n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - m_A= 10 m_B=10 hello world \n",
" - 请按任意键继续. . ."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 4. 递增运算符"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① 递增运算符重载:通过重载递增运算符,实现自己的整型数据。\n",
"\n",
"② 前置递增返回的是引用,后置递增返回的是值。"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"\n",
"//重载递增运算符\n",
"\n",
"class MyInteger\n",
"{\n",
" friend ostream& operator<<(ostream& cout, MyInteger myint);\n",
"\n",
"public:\n",
" MyInteger()\n",
" {\n",
" m_Num = 0;\n",
" }\n",
" \n",
" //重载前置++运算符,返回引用是为了一直对一个数据进行递增操作,而返回值并不是一直对一个数据进行递增操作 \n",
" MyInteger& operator++()\n",
" {\n",
" //先进行++运算\n",
" m_Num++;\n",
"\n",
" //再将自身做一个返回\n",
" return *this; //把自身做一个返回\n",
" }\n",
"\n",
" //重载后置++运算符 int代表占位参数可以用于区分前置和后置递增\n",
" //后置递增不能返回引用因为temp是局部变量如果返回temp当程序运行完后变量就释放了再调用temp就是非法操作了 \n",
" MyInteger operator++(int)\n",
" {\n",
" //先记录当时结果\n",
" MyInteger temp = *this;\n",
" //后 递增\n",
" m_Num++;\n",
" //最后将记录结果做返回\n",
" return temp;\n",
" }\n",
"private:\n",
" int m_Num;\n",
"};\n",
"\n",
"//只能利用全局函数重载左移运算符\n",
"ostream & operator<<(ostream &cout, MyInteger myint) //本质 operator << (cout , p) , 简化 cout << p\n",
" //cout是别名这里可以取out、kn...\n",
" //cout为ostream输出流数据类型 \n",
"{\n",
" cout << myint.m_Num;\n",
"\n",
" return cout;\n",
"}\n",
"\n",
"void test01()\n",
"{\n",
" MyInteger myint;\n",
"\n",
" cout << ++(++myint) << endl;\n",
" cout << myint << endl;\n",
"}\n",
"\n",
"void test02()\n",
"{\n",
" MyInteger myint;\n",
"\n",
" cout << myint++ << endl;\n",
" cout << myint << endl;\n",
"\n",
"}\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
" test02();\n",
"\n",
" /*\n",
" int a = 0;\n",
" cout << ++(++a) << endl; //运行结果为2\n",
" cout << a << endl; //运行结果为2表示一直对一个数据进行递增\n",
" */\n",
"\n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - 2 \n",
" - 2 \n",
" - 0 \n",
" - 1 \n",
" - 请按任意键继续. . ."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 5. 赋值运算符"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① C++编译器至少给一个类添加4个函数\n",
"\n",
"1. 默认构造函数(无参,函数体为空)\n",
"2. 默认析构函数(无参,函数体为空)\n",
"3. 默认拷贝构造函数,对属性进行值拷贝\n",
"4. 赋值运算符operator=,对属性进行值拷贝\n",
"5. 如果类中有属性指向堆区,做赋值操作时也会出现浅拷贝问题。"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"\n",
"//重载赋值运算符\n",
"\n",
"class Person\n",
"{\n",
"public:\n",
" Person(int age)\n",
" {\n",
" m_Age = new int(age);\n",
" }\n",
" \n",
" ~Person()\n",
" {\n",
" if (m_Age != NULL)\n",
" {\n",
" delete m_Age;\n",
" m_Age = NULL;\n",
" }\n",
" }\n",
"\n",
" //重载 赋值运算符\n",
" //如果返回的是值,而不是引用,是创建一个拷贝函数,返回的是一个副本,而不是自身\n",
" Person& operator=(Person& p)\n",
" {\n",
" //编译器默认是提供浅拷贝\n",
" //m_Age = p.m_Age;\n",
"\n",
" //浅拷贝带来的问题是,当创建数据在堆区时,析构代码导致内存重复释放,报错\n",
"\n",
" //应该先判断是否有属性在堆区,如果有先释放干净,然后再深拷贝\n",
" if (m_Age != NULL)\n",
" {\n",
" delete m_Age;\n",
" m_Age = NULL;\n",
" }\n",
"\n",
" //深拷贝\n",
" m_Age = new int(*p.m_Age);\n",
"\n",
" //返回对象本身\n",
" return *this;\n",
" }\n",
"\n",
" int *m_Age;\n",
"};\n",
"\n",
"void test01()\n",
"{\n",
" Person p1(18);\n",
"\n",
" Person p2(20);\n",
"\n",
" Person p3(23);\n",
"\n",
" p3 = p2 = p1; //赋值操作\n",
"\n",
" cout << \"p1的年龄为\" << *p1.m_Age << endl;\n",
"\n",
" cout << \"p2的年龄为\" << *p2.m_Age << endl;\n",
"\n",
" cout << \"p3的年龄为\" << *p3.m_Age << endl;\n",
"\n",
"\n",
"}\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
"\n",
" /*\n",
" \n",
" int a = 10;\n",
" int b = 20;\n",
" int c = 30;\n",
" \n",
" c = b = a;\n",
"\n",
" cout << \"a= \" << a << endl;\n",
" cout << \"b= \" << b << endl;\n",
" cout << \"c= \" << c << endl;\n",
" */\n",
"\n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - p1的年龄为18 \n",
" - p2的年龄为18 \n",
" - p3的年龄为18 \n",
" - 请按任意键继续. . ."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 6. 关系重载运算符"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"#include<string>\n",
"\n",
"//重载关系运算符\n",
"\n",
"class Person\n",
"{\n",
"public:\n",
" Person(string name, int age)\n",
" {\n",
" m_Name = name;\n",
" m_Age = age;\n",
" }\n",
"\n",
" //重载 == 号\n",
" bool operator==(Person& p)\n",
" {\n",
" if (this->m_Name == p.m_Name && this->m_Age == p.m_Age)\n",
" {\n",
" return true;\n",
" }\n",
" return false;\n",
" }\n",
"\n",
" bool operator!=(Person& p)\n",
" {\n",
" if (this->m_Name != p.m_Name && this->m_Age != p.m_Age)\n",
" {\n",
" return true;\n",
" }\n",
" return false;\n",
" }\n",
"\n",
" string m_Name;\n",
" int m_Age;\n",
"};\n",
"\n",
"void test01()\n",
"{\n",
" Person p1(\"Tom\", 17);\n",
"\n",
" Person p2(\"Jerry\", 18);\n",
"\n",
" if (p1 == p2)\n",
" {\n",
" cout << \"p1和p2是相等的\" << endl;\n",
" }\n",
" else\n",
" {\n",
" cout << \"p1和p2是不相等的\" << endl;\n",
"\n",
" }\n",
"\n",
" if (p1 != p2)\n",
" {\n",
" cout << \"p1和p2是不相等的\" << endl;\n",
" }\n",
" else\n",
" {\n",
" cout << \"p1和p2是相等的\" << endl;\n",
"\n",
" }\n",
"\n",
"\n",
"}\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
" \n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - p1和p2是不相等的 \n",
" - p1和p2是不相等的 \n",
" - 请按任意键继续. . ."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# 7. 函数调用运算符重载"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"① 函数调用运算符()也可以重载。\n",
"\n",
"② 由于重载后使用的方式非常像函数的调用,因此称为仿函数。\n",
"\n",
"③ 仿函数没有固定写法,非常灵活。"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"#include <iostream>\n",
"using namespace std;\n",
"#include<string>\n",
"\n",
"//函数调用运算符重载\n",
"\n",
"//打印输出类\n",
"class MyPrint\n",
"{\n",
"public:\n",
"\n",
" //重载函数调用运算符\n",
" void operator()(string test)\n",
" {\n",
" cout << test << endl;\n",
" }\n",
"\n",
"};\n",
"\n",
"//正常函数\n",
"void MyPrint02(string test)\n",
"{\n",
" cout << test << endl;\n",
"}\n",
"\n",
"void test01()\n",
"{\n",
" MyPrint myPrint;\n",
"\n",
" myPrint(\"hello world\");\n",
"\n",
"}\n",
"\n",
"//仿函数非常灵活,没有固定的写法\n",
"//加法类\n",
"class MyAdd\n",
"{\n",
"public:\n",
" int operator()(int num1, int num2)\n",
" {\n",
" return num1 + num2;\n",
" }\n",
"};\n",
"\n",
"void test02()\n",
"{\n",
" MyAdd myadd;\n",
" int ret = myadd(100,100);\n",
" cout << \"ret = \" << ret << endl;\n",
"\n",
" //匿名函数对象\n",
" cout << MyAdd()(100, 100) << endl;\n",
"\n",
" // MyAdd()为创建一个匿名对象,匿名对象的特点为当前行执行完立即释放\n",
"}\n",
"\n",
"int main()\n",
"{\n",
" test01();\n",
"\n",
" MyPrint02(\"hello world\"); //由于使用起来非常类似于函数调用,因此称为仿函数\n",
"\n",
" test02();\n",
"\n",
" system(\"pause\");\n",
"\n",
" return 0;\n",
"\n",
"}"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"运行结果: \n",
" - hello world \n",
" - hello world \n",
" - ret = 200 \n",
" - 200 \n",
" - 请按任意键继续. . ."
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3.6.3",
"language": "python",
"name": "python3.6.3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.6.3"
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"toc": {
"base_numbering": 1,
"nav_menu": {},
"number_sections": false,
"sideBar": true,
"skip_h1_title": false,
"title_cell": "Table of Contents",
"title_sidebar": "Contents",
"toc_cell": false,
"toc_position": {},
"toc_section_display": true,
"toc_window_display": true
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"nbformat": 4,
"nbformat_minor": 4
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