代码有点看不懂

#include <iostream>
using namespace std;


struct student
{
    long number;
    float score;
    student * next;
};
student * head;
student * create()
{
    student * ps;
    student * pend;
    ps=new student;
    cin>>ps->number;cin>>ps->score;
    head=NULL;
    pend=ps;
    while(ps->number!=0)
    {
        if(head==NULL)
            head=ps;
        else
            pend->next=ps;
        pend=ps;
        ps=new student;
        cin>>ps->number>>ps->score;
    }
    pend->next=NULL;
    delete ps;
    return(head);
}
void showlist(student* head)
{
    cout<<"now the items of list are";
    while(head)
    {
        cout<<head->number<<","<<head->score<<endl;
        head=head->next;
    }
}
void main()
{
    showlist(create());
}
上面红色代码是一样的，有什么不同的作用吗？