在跟郝斌的数据结构，然后跟着他打了一遍链表的代码，但是排序那一块的函数死活输出不了，有没有人能够看一下……

include

include

include

typedef struct node
{
int data;
struct node * pnext;
}node, *pnode;

pnode create_list(void);
void traverse_list(pnode phead);
bool is_empty(pnode phead);
int lenth_list(pnode);
//bool insert_list(pnode , int ,int);
//bool delete_list(pnode, int ,int*);
void sort_list(pnode );

int main (void)
{
pnode phead = NULL;

phead = create_list();
traverse_list(phead);

int len = lenth_list(phead);
printf("链表长度：%d",len);


sort_list(phead);
traverse_list(phead);

return 0;

}

pnode create_list(void)
{
int len;
int i;
int val;

pnode phead = (pnode) malloc(sizeof(node));
if(NULL == phead)
{
    printf("false\n");
    exit(-1);
}

pnode ptail = phead;
ptail -> pnext = NULL; 

printf("please input the number of  list:");
scanf("%d",&len);


for( i = 0; i"please input the val of the %d:",i+1);
    scanf("%d",&val);
    
    pnode pnew = (pnode) malloc(sizeof(node));
    if(NULL == pnew)
    {
      printf("false\n");
      exit(-1);
    }
    
    pnew->data = val;
    ptail->pnext = pnew;
    pnew->pnext = NULL; 
    ptail = pnew;
    
}

return phead;

}

void traverse_list(pnode phead)
{
pnode p = phead->pnext;

while(NULL != p)
{
    printf("%d\n",p->data);
    p = p->pnext;
}
printf("\n");

return;

}

int lenth_list(pnode phead)
{
pnode p = phead->pnext;
int len = 0;

while (NULL != p)
{
    ++len;
    p->pnext;
}
return len;

}

void sort_list(pnode phead)
{
int i, j, k;
int len = lenth_list(phead);
pnode p,q;

for (i=0,p=phead->pnext; i < len-1; ++i , p = p->pnext)
{
    for(j=i+1,q=p->pnext; jpnext)
    {
        if (p->data > q->data)
        
        {
            k = p->data;
            p->data = q->data;
            q->data = k;
        
        }
    }
            
}
    
return ;

}

只有前两个函数输出结果了，长度和排列都没有结果