c++菱形继承最派生类无法使用虚基类成员变量？求解答或线索

先上代码

.h

#include <iostream>
using namespace std;
#ifndef PERSON_H
#define PERSON_H
//虚基类Person
class Person
{
protected:
    string name, id, sex;

public:
    Person(string _name, string _id, string _sex);
    void print_info();
};
//派生类Student
class Student : virtual public Person
{
protected:
    string major, grade;

public:
    Student(string _name, string _id, string _sex, string _major, string _grade);
    void print_info();
};
//派生类Assistant
class Assistant : virtual public Person
{
protected:
    string school;
    double salary;

public:
    Assistant(string _name, string _id, string _sex, string _school, double _salary);
    void print_info();
};
//最派生类Studen_assistant
class Student_assistant : public Student, public Assistant
{
public:
    Student_assistant(string _name, string _id, string _sex,
                      string _major, string _grade, string _school, double _salary);
    void print_info();
};
#endif

.cpp

#include "person.h"
Person::Person(string _name, string _id, string _sex)
{
    name = _name;
    id = _id;
    sex = _sex;
};
void Person::print_info()
{
    printf("name:%s  id:%s  sex:%s\n", name.c_str(), id.c_str(), sex.c_str());
};
Student::Student(string _name, string _id, string _sex, string _major, string _grade)
    : Person(_name, _id, _sex)
{
    major = _major;
    grade = _grade;
};
void Student::print_info()
{
    printf("name:%s  id:%s  sex:%s  major:%s  grade:%s\n",
           name.c_str(), id.c_str(), sex.c_str(), major.c_str(), grade.c_str());
};
Assistant::Assistant(string _name, string _id, string _sex, string _school, double _salary)
    : Person(_name, _id, _sex)
{
    school = _school;
    salary = _salary;
};
void Assistant::print_info()
{
    printf("name:%s  id:%s  sex:%s  school:%s  salary:%.2f\n",
           name.c_str(), id.c_str(), sex.c_str(), school.c_str(), salary);
};
Student_assistant::Student_assistant(string _name, string _id, string _sex,
                                     string _major, string _grade, string _school, double _salary)
    : Person(_name, _id, _sex), Student(_name, _id, _sex, _major, _grade), Assistant(_name, _id, _sex, _school, _salary)
{
    //test
    printf("name:%s  id:%s  sex:%s  major:%s  grade:%s  school:%s  salary:%.2f\n",
           name.c_str(), id.c_str(), sex.c_str(), major.c_str(), grade.c_str(), school.c_str(), salary);
    //test
}
void Student_assistant::print_info()
{
    //test
    cout << major << name << endl;
    //test
    printf("name:%s  id:%s  sex:%s  major:%s  grade:%s  school:%s  salary:%.2f\n",
           name.c_str(), id.c_str(), sex.c_str(), major.c_str(), grade.c_str(), school.c_str(), salary);
}

main.cpp

#include "person.h"
inline int U(char *str)
{
    return (str[0] + (str[1] ? U(str + 1) : 0));
};
constexpr inline int U(const char *str)
{
    return (str[0] + (str[1] ? U(str + 1) : 0));
};
int main()
{
    string name = "a", id = "12", sex = "male", major = "math", grade = "freshman", school = "huft";
    double salary = 1000;
    Person a(name, id, sex);
    Student b(name, id, sex, major, grade);
    Assistant c(name, id, sex, school, salary);
    Student_assistant d(name, id, sex, major, grade, school, salary);
    char str[2];
    cout << "please operate\nP:person   S:student   A:assiatant   SA:student-assistant   E:exit" << endl;
    for (bool bo = true; bo;)
    {
        cin >> str;
        switch (U(str))
        {
        case U("P"):
            a.print_info();
            break;
        case U("S"):
            b.print_info();
            break;
        case U("A"):
            c.print_info();
            break;
        case U("SA"):
            d.print_info();
            break;
        case U("E"):
            bo = false;
            break;
        default:
            cout << "command wrong" << endl;
            break;
        }
    }
    return (0);
}

跑出来出错

非虚基类成员变量major可以正常输出(math)，虚基类成员变量name输出出错，但是在构造函数中都能正常输出

此外我还试了这么写

...
void Student_assistant::print_info()
{
  Student::print_info();
  cout << "school:" << school << "   salary:" << salary << endl;
}
...

结果也不行，报错位置转到了Student::print_info()

求解答或者线索
上网找了好久也找不到问题所在，我快怀疑是我的编译器出问题了，编辑器用的vscode，编译器用的c++11
另外如果代码中有值得优化的地方恳请指教

我正常运行，我只修改了这里

void Student_assistant::print_info()
{
    //test
    cout << major.c_str() << name.c_str() << endl;
    //test
    printf("name:%s  id:%s  sex:%s  major:%s  grade:%s  school:%s  salary:%.2f\n",
        name.c_str(), id.c_str(), sex.c_str(), major.c_str(), grade.c_str(), school.c_str(), salary);
}

cout << major.c_str() << name.c_str() << endl;
string转了char