这个为什么报错能帮我找一找错误吗？

Question

#include<iostream>
#include<string>
using namespace std;
class Person
{
    friend ostream& operator<<(ostream& cout, Person p);
public:
    Person(int a);
    ~Person();
    Person& operator=(Person& p)
    {
        if (age != NULL)
        {
            delete(age);
            age = NULL;
        }
        this->age = new int(*p.age);
        return *this;
    }
private:
    int* age;
};
ostream& operator<<(ostream& cout, Person p)
{
    cout << *p.age << endl;
    return cout;
}
Person::Person(int a)
{
    this->age = new int(a);
}
Person::~Person()
{
    if (age != NULL)
    {
        delete(age);
        age = NULL;
    }
}
void test01()
{
    Person a(10);
    Person b(20);
    Person c(30);
    a = b = c;
    cout << a << b << c;
}
int main()
{
    test01();
    return 0;
}

Answer 1

this->age = new int(*p.age);
由于age是私有变量，所以不能这么访问，必须增加获取age的函数才行
int getAge() {return age;}
this->age = new int(p->getAge());

ostream& operator<<(ostream& cout, Person p)
{
cout << *p.age << endl;
return cout;
----这里由于p不是指针对象，所以cout<<p.age就可以了