一個帶有以類對象為成員的類怎么重載才能顯示對象成員的信息?

可以重載輸出流運算符 << 來實現。具體實現如下：

#include<iostream>
using namespace std;
class Person{
public:
    int age;
    string name;
    friend ostream& operator<<(ostream& out, const Person& p){
        out << "name: " << p.name << " age: " << p.age;
        return out;
    }
};
class Student{
public:
    int id;
    Person person;
    friend ostream& operator<<(ostream& out, const Student& s){
        out << "id: " << s.id << " person: " << s.person;
        return out;
    } 
};
int main(){
    Person p;
    p.age = 20;
    p.name = "Tom";
    Student s;
    s.id = 1;
    s.person = p;
    cout << s << endl; //輸出: id: 1 person: name: Tom age: 20
    return 0;
}

在上述代碼中，Person 類重載了 << 運算符，將姓名和年齡輸出。Student 類重載了 << 運算符，將學號和 Person 對象輸出，這樣在輸出 Student 對象時就可以輸出所有信息了。