c++重载

谁践踏了优雅 2022-09-11 04:12 178阅读 0赞

### 重载 ###

*  自增运算符重载
 *  赋值运算符重载
 *  关系运算符重载

# 自增运算符重载 #

#include <iostream>
    using namespace std;
    class Person { 
       friend ostream& operator<<(ostream &cout, Person p);
    public:
        Person(int x) { 
            m_Age = x;
        }
        //前置++运算符重载
        Person& operator++() { 
            m_Age++;
            return *this;
        }
    
        //后置++运算符
        Person operator++(int) { 
            //先记录当时结果
    
            Person temp = *this;
    
            m_Age++;
            return temp;
        }
    
    
    private:
        int m_Age;
    };
    
    
    ostream& operator<<(ostream &cout,Person p) { 
    
        cout << p.m_Age;
        return  cout;
    }
    
    
    void test1() { 
        Person p1(10);
        cout << ++p1<<endl;
    
    }
    
    
    
    void test2() { 
        Person p1(10);
        cout << p1++ << endl;
        cout << p1 << endl;
    
    }
    
    int main()
    { 
        //test1();
        test2();
        
    
        //std::cout << "Hello World!\n";
    }

# 赋值运算符重载 #

// ConsoleApplication8.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
    //
    
    #include <iostream>
    using namespace std;
    class Person { 
       friend ostream& operator<<(ostream &cout, Person p);
    public:
        Person(int x) { 
            m_Age = new int(x);
        }
    
        ~Person() { 
            while (m_Age != NULL) { 
                delete m_Age;
                m_Age = NULL;
            }
        }
        //赋值运算符重载
        Person & operator=(Person& p) { 
            //应该先判断是否有属性在堆区
            if (m_Age != NULL) { 
                delete m_Age;
                m_Age = NULL;
            }
            this->m_Age = new int(*p.m_Age);
            //返回对象本身
            return *this;
        }
    
    public:
        int *m_Age;
    };
    
    
    
    void test01() { 
        Person p1(10);
        Person p2(20);
        Person p3(30);
       p3= p2 = p1;
        cout << *p1.m_Age << endl;
        cout << *p2.m_Age << endl;
        cout << *p3.m_Age << endl;
    }
    
    
    int main()
    { 
        test01();
        //test2();
        
    
        //std::cout << "Hello World!\n";
    }

# 关系运算符重载 #

#include <iostream>
    using namespace std;
    class Person { 
      
    public:
        Person(int x,string str) { 
            m_Age = x;
            m_Name = str;
        }
    
        ~Person() { 
          
        }
      
        //关系运算符重载，==
        bool operator==(Person &p) { 
            if (this->m_Age == p.m_Age && this->m_Name == p.m_Name) { 
                return true;
            }
            else { 
                return false;
            }
        }
    
    private:
        int m_Age;
        string m_Name;
    };
    void test01() { 
        Person p1(10,"张三");
        Person p2(10,"张三");
        if (p1 == p2) { 
            cout << "两个对象相等" << endl;
        }
        else { 
            cout << "两个对象不相等" << endl;
        }
      
    }
    
    
    int main()
    { 
        test01();
        //std::cout << "Hello World!\n";
    }