Numerical-Algorithms-2020/class_10.cpp at master · EXthan/Numerical-Algorithms-2020

282 lines (164 loc) · 3.62 KB
#include <iostream>
using namespace std;
//c++编译器至少给一个类添加4个函数
//默认构造函数(无参，函数体为空)
//默认析构函数(无参，函数体为空)
//默认拷贝构造函数，对属性进行值拷贝
//赋值运算符 operator=, 对属性进行值拷贝
//如果类中有属性指向堆区，做赋值操作时也会出现深浅拷贝问题
class Person
    Person(int age)
        //将年龄数据开辟到堆区
        m_Age = new int(age); //set initial value as age
    //重载赋值运算符 
    Person& operator=(Person &p)
        if (m_Age!= NULL)
            delete m_Age;
            m_Age = NULL;
        //编译器提供的代码是浅拷贝
        //m_Age = p.m_Age;
        //提供深拷贝 解决浅拷贝的问题
        m_Age = new int(*p.m_Age);//set *p.m_Age as init value
        //返回自身
        return *this;
    ~Person()
        if (m_Age != NULL)
            delete m_Age;
            m_Age = NULL;
    //年龄的指针
    int *m_Age;
void test01()
    Person p1(18);
    Person p2(20);
    Person p3(30);
    p3 = p2 = p1; //赋值操作
    cout << "p1的年龄为：" << *p1.m_Age << endl;
    cout << "p2的年龄为：" << *p2.m_Age << endl;
    cout << "p3的年龄为：" << *p3.m_Age << endl;
    test01();
    //int a = 10;
    //int b = 20;
    //int c = 30;
    //c = b = a;
    //cout << "a = " << a << endl;
    //cout << "b = " << b << endl;
    //cout << "c = " << c << endl;
    return 0;
//重载关系运算符，可以让两个自定义类型对象进行对比操作
//class Person
//    Person(string name, int age)
//        this->m_Name = name;
//        this->m_Age = age;
//    bool operator==(Person & p)
//        if (this->m_Name == p.m_Name && this->m_Age == p.m_Age)
//        {
//            return true;
//        }
//        else
//        {
//            return false;
//        }
//    bool operator!=(Person & p)
//        if (this->m_Name == p.m_Name && this->m_Age == p.m_Age)
//        {
//            return false;
//        }
//        else
//        {
//            return true;
//        }
//    string m_Name;
//    int m_Age;
//void test01()
//    Person a("孙悟空", 18);
//    Person b("孙悟空", 18);
//    if (a == b)
//        cout << "a和b相等" << endl;
//        cout << "a和b不相等" << endl;
//    if (a != b)
//        cout << "a和b不相等" << endl;
//        cout << "a和b相等" << endl;
//int main()
//    test01();
//    return 0;
// 函数调用运算符重载
//函数调用运算符 () 也可以重载
//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
//仿函数没有固定写法，非常灵活
//class MyPrint
//    void operator()(string text)
//        cout << text << endl;
//void test01()
//    //重载的（）操作符 也称为仿函数
//    MyPrint myFunc;
//    myFunc("hello world");
//class MyAdd
//    int operator()(int v1, int v2)
//        return v1 + v2;
//void test02()
//    MyAdd add;
//    int ret = add(10, 10);
//    cout << "ret = " << ret << endl;
//    //匿名对象调用  
//    cout << "MyAdd()(100,100) = " << MyAdd()(100, 100) << endl;
//int main()
//    test01();
//    test02();
//    return 0;
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