主函数执行完class就结束了


#include 
#include 
using namespace std;
typedef struct student
{
    char name[20];
    char num[20];
    struct student *next;
}Lnode,*linklist;
class Class
{public:
    Lnode *head;
    static int stunum;
    static void printfstunum();
Class()
{
    head=(linklist)malloc(sizeof(Lnode));
    head->next=NULL;
    Lnode *p=head->next;
    cout<<"请输入姓名与学号"<>p->name>>p->num;
}
void insertstu(Lnode *head)
{    Lnode *p;
     p=head->next;
        while(p!=NULL)
        {
           p=p->next;
        }
            if(p==NULL)
            {
            cout<<"请输入学生信息"<>p->name>>p->num;
            }
}
void showstu(Lnode *head)
{
    Lnode *p=head->next;
    while(p!=NULL)
    {
        cout<name<<","<num<next;
    }
}




};
int Class::stunum=20;
int main()
{   Class a;
    Lnode *headstu;
    headstu=(linklist)malloc(sizeof(Lnode));
    headstu->next=NULL;
    headstu=a.head;
    a.showstu(headstu);
    a.printfstunum();
    return 0;
}
void Class::printfstunum()
{

    cout<<"班级人数为:"<

headstu=a.head;
你前面白给headstu分配内存了，这指针指向直接改了？