#c++#报错下附代码以及目的，求解决

上代码:

#include <iostream>
#include <windows.h>
#include <string>
#include <cmath>

using namespace std; 
struct Student{
    string name;
    int age;
    string sex;
} ;
struct Teacher{
    string name;
    int age;
    string sex;
    int teachage;
};
struct defClass{
    string name;
    int grade;
    int cla;
    int wstudents;
    Student studentslist[wstudents];
    int teachers;
    Teacher techerslist[teachers];


};
int main(){
    
    defClass p;
    Student st1={"张三",12,"男"};
    Student st2={"李四",11,"男"};
    p.wstudents=2;
    p.studentslist{st1,st2};
    cout<<p.studentslist[1].age<<endl;
    return 0;
}

报错:

p.studentslist{st1,st2};

这是什么语法？