C++单向链表的反转

#include <iostream>
#include <cstdio>
#include <assert.h>
typedef struct student
{
    int score;
    struct student *next;
}linklist;
linklist *creat (int n)
{
    linklist *head ,*node ,*end;
    head = (linklist*) malloc(sizeof (linklist));
    end = head ;
    printf("请输入第0个节点的分数\n");
    scanf("%d",&(head->score));
    for (int i = 1; i < n; ++i) {
        node = (linklist *) malloc(sizeof(linklist));
        printf("请输入第%d个节点的分数\n",i);
        scanf("%d",&(node->score));
        end->next = node;
        end =node;
    }
    end->next=NULL;
    return head;
}
void change(linklist *list , int n)
{
    assert(n>=0);
    int i = 0;
    linklist *t = list;
    while ( i<n && t->next!=NULL)
    {
        i++;
        t = t->next;
    }

    if (i==n)
    {
        printf("please put the numbers you want to change\n");
        scanf("%d",&(t->score));
    }
    else
    {
        printf("node isn't exit\n");
    }

}
linklist * delete_node(linklist *list ,int n)
{
    linklist * t =NULL;
    linklist * in = list;
    int i=0;
    assert(n>=0);
    if (n==i)
    {
        if (list->next!= nullptr)
        {

            list=list->next;
            free(in);
            return list;
        }
        else
        {
            free(list);
            return NULL;
        }
//        free(list);

    }
    for (i = 0;  i<n-1 ; i++) {
        in=in->next;
    }
    if (in->next!= nullptr)
    {
        t = in->next;
        in->next=t->next;
        free(t);
        return list;
    } else
    {
        printf("节点不存在");
    }
}
void insertlinklist(linklist *p,int n)//n表示你插入的节点是第几个节点，head为第0个 head后的node为第一个节点。
{
    linklist *t,*medium;
    assert(n>=0);
    if (n==0){
        printf("please input the value you want to insert");
        scanf("%d",&(t->score));
        t->next=p;
    }
    else if (n>0)
    {
        for (int i = 0; i < n && p->next!=NULL; ++i) {
            p=p->next;
        }
        scanf("%d",&(t->score));
        t->next=p->next;
        p->next=t;
    } else
    {
        printf("error");
    }

}
linklist * reverse_linklist(linklist *a )
{
    linklist *next= a;
    linklist *pre = NULL;
    while (next!= NULL)
    {
        next = next->next;
        a->next =pre;
        pre = a;
        a=next;
    }
    return pre;
}
int main()
{
    linklist *a= creat(5);
    int node_index=0;
//    while (a!=NULL)
//    {
////        printf("第%d个节点的值是: %d\n",node_index,a->score);
//        std::cout<<"第"<<node_index<<"个的分数是"<<a->score<<std::endl;
//        node_index++;
//        a=a->next;
//    }
//    change(a,4);
//   a= delete_node(a,3);
   a= reverse_linklist(a);
    while (a!=NULL)
    {
//      printf("第%d个节点的值是: %d\n",node_index,a->score);
        std::cout<<"第"<<node_index<<"个的分数是"<<a->score<<std::endl;//第0个就是头部节点。。。
        node_index++;
        a=a->next;
    }

}