class Student {public: Student(int n, string nam ) {num=n; name=nam; } void display() {cout<<"num:"<<num<<endl; cout<<"name:"<<name<<endl; } protected: int num; string name; }; class Student1: public Student {public: ▁▁▁(3分) {age=a; } void show( ) {display(); cout<<"age: "<<age<<endl; } private: int age; }; class Student2:public Student1 {public: ▁▁▁(3分) {score=s;} void show_all() {show(); cout<<"score:"<<score<<endl; } private: int score; };

在 class Student1 中，应该定义一个带参数的构造函数，将 age 初始化为给定的值。应该写成：`Student1(int n, string nam, int a): Student(n, nam), age(a) {}`。

在 class Student2 中，应该定义一个带参数的构造函数，将 score 初始化为给定的值。应该写成：`Student2(int n, string nam, int a, int s): Student1(n, nam, a), score(s) {}`。