请问哪里有问题，无法编译

Question

#include<iostream>
#include<string.h> 
using namespace std;
class Student
{
    private:
        int Id;
        string Name;
        float Sco;
        public:
            Student(int id=0,string name=0,float sco=0)
            {
                Id=id;
                Name=name;
                Sco=sco;
            }
            void Add(Student &c1,Student &c2,Student &c3)
            {
                Student c;
                c.Sco=(c1.Sco+c2.Sco+c3.Sco)/3;
                cout<<c.Sco<<endl;
            }
            void PrintAll(Student &c1,Student &c2,Student &c3)
            {
                cout<<c1.Id<<c1.Name<<c1.Sco<<endl;
                cout<<c2.Id<<c2.Name<<c2.Sco<<endl;
                cout<<c3.Id<<c3.Name<<c3.Sco<<endl;    
            }                                                                                           
};

int main()
{
    Student c1(01,"小明",96),c2(02,"小红",85),c3(03,"小兰",76);
    Add(c1,c2,c3);
    PrintAll(c1,c2,c3);
    return 0;
}

Answer 1

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

class Student
{
    private:
    int Id;
    string Name;
    float Sco;
    public:
        Student(int id=0,string name="",float sco=0)
        {
            Id=id;
            Name=name;
            Sco=sco;
        }
        static void Add(Student &c1,Student &c2,Student &c3)
        {
            Student c;
            c.Sco=(c1.Sco+c2.Sco+c3.Sco)/3;
            cout<<c.Sco<<endl;
        }
        static void PrintAll(Student &c1,Student &c2,Student &c3)
        {
            cout<<c1.Id<<c1.Name<<c1.Sco<<endl;
            cout<<c2.Id<<c2.Name<<c2.Sco<<endl;
            cout<<c3.Id<<c3.Name<<c3.Sco<<endl;
        }
};

int main()
{
    Student c1(01,"小明",96),c2(02,"小红",85),c3(03,"小兰",76);
    Student::Add(c1,c2,c3);
    Student::PrintAll(c1,c2,c3);

    return 0;
}