这个题里面的stu1到底怎么用？大佬们救救孩子吧

#include<stdio.h>

class Student{

      private:
              int number;
              int score;
      public :
              Student(int n=0,int s=0):number(n),score(s){}
              void input (int n,int s){
                   number = n;
                   score  = s;
              }
              void setscore(int s){
                  score  = s;
              }
              void outprint(void){
                  printf("num=%d,score=%d\n",number,score);
              }
};

int main()
{
   Student s1(101,85); //定义学生对象s1
   s1.outprint();      //打印输出

   Student *p=&s1; //通过指向对象的指针访问对象中的成员
   p->outprint();

   Student &stu1=s1;//通过对象的引用变量来访问对象中的成员
   stu1.setscore(70);
   stu1.outprint();
   s1.outprint();    
   
   system("pause");
   return 0;
}

int main()
{

   Student s1 = new Student(); //定义学生对象s1
   s1.setscore();             //输入s1成绩
   s1.outprint();             //打印输出

   Student stu1;

   stu1 = s1; // stu1和s1均为一个地址，指向同一个地址

   stu1.setscore();        //利用引用修改s1成绩

   s1.outprint();          //打印输出看结果
   stu1.outprint();

}