C语言 单向链表选择法排序

typedef struct FiledataNode
{
char FileName[256]; // the length is 256 for filename, liangls
char datetimeOriginal[20];
char fullpath[PHOTO_MAX_PATH];
/*other item*/
struct FiledataNode *prior;
struct FiledataNode *next;
}FiledataNode;


AF_ERROR_CODE VirtualfolderSort(FiledataNode *phead)
{
FiledataNode *i,*j,*t,*p,*max,tmp;

if(phead == NULL)
return AF_STATUS_FAIL;

p=phead;
for(i=p;i->next!=NULL;i=i->next)
{
max=i;
for(j=i->next;j!=NULL;j=j->next)
{
if(j->datetimeOriginal[0] > max->datetimeOriginal[0] )
{
max = j;
if(max->datetimeOriginal[0] != i->datetimeOriginal[0])
{
tmp = *max;
*max = *i;
*i = tmp;
t = max->next;
max->next= i->next;
i->next = t;
max = i;
}
}

}
}
while(p->next != NULL)
{
AF_PRINTF("%s",p->datetimeOriginal);
p = p->next;
}
AF_PRINTF("%s",p->datetimeOriginal);

return (phead);

}