[求助]关于一个嵌套类和有元的问题

#include <iostream>
#include <string>
using namespace std;

class Nwpu;

class Student {

private:
string name;
friend class Nwpu;
public :
Student();
void display();
};

Student::Student() {
name = "RJ010502_李强";
}

void Student::display() {
cout << name;
}

class Nwpu {

public:
void diplay();
class Software {
private:
string banji;
public:
Software();
void display();
};
};

void Nwpu::diplay() {
cout << "西北工业大学";
}

Nwpu::Software::Software() {
banji = "软件学院";
}

void Nwpu::Software::display() {
cout << this->banji << Student::name << endl;
}

void main() {

Nwpu xbgy;
Nwpu::Software rjxy;
Student stu;

xbgy.diplay();
rjxy.display();
stu.display();
}

就是这个方法有问题Student::name老是报错
是我有元声明有问题？还是别的
其实我就是想用嵌套类调用外部类的私有变量

void Nwpu::Software::display() {
cout << this->banji << Student::name << endl;
}

谢谢