nhơ` giúp đơ~ 1 xíu

#include<stdio.h>
#include<malloc.h>
struct node
{
int info;
struct node *prev;
struct node *next;
};
typedef struct node *nodeptr;
nodeptr newnode()
{
nodeptr p;
p=(nodeptr)malloc(sizeof(struct node));
return p;
}
void Init(nodeptr *phead)
{
*phead=NULL;
}
void freenode(nodeptr p)
{
free(p);
}
int IsEmpty(nodeptr phead)
{
if(phead==NULL)
return 1;
return 0;
}
void InsertFirst(nodeptr *phead,int x)
{
nodeptr p;
p=newnode();
p->info=x;
if(*phead==NULL)
{
*phead=p;
p->prev=*phead;
p->next=*phead;
}
else
{
p->prev=(*phead)->prev;
(*phead)->prev->next=p;
(*phead)->prev=p;
p->next=*phead;
*phead=p;
}
}
void InserLast(nodeptr *phead,int x)
{
nodeptr p;
p=newnode();
p->info=x;
if(*phead==NULL)
{
*phead=p;
p->prev=*phead;
p->next=*phead;
}
else
{
p->prev=(*phead)->prev;
p->next=(*phead)->prev->next;
(*phead)->prev->next=p;
(*phead)->prev=p;
}
}
void ShowList(nodeptr phead)
{
nodeptr p;
if(phead==NULL)
{
printf("Danh sach rong\n");
return;
}
p=phead;

do
{
printf("%d ",p->info);

p=p->next;
}
while(p!=phead);

}
void DeleteFirst(nodeptr *phead)
{
nodeptr p;
if(*phead==NULL)
{
printf("Danh sach rong\n");
return;
}
else if((*phead)->next==*phead)
{
p=*phead;
freenode(p);
*phead=NULL;
}
else
{
p=*phead;
p->prev->next=p->next;
p->next->prev=p->prev;
(*phead)=(*phead)->next;
freenode(p);
}
}
void DeleteLast(nodeptr *phead)
{
nodeptr p;
if(*phead==NULL)
{
printf("Danh sach rong\n");
return;
}
else if((*phead)->next==*phead)
{
p=*phead;
freenode(p);
*phead=NULL;
}
else
{
p=(*phead)->prev;
(*phead)->prev=p->prev;
p->prev->next=*phead;
freenode(p);
}
}
void ShowInvert(nodeptr phead)
{
nodeptr p;
if(phead==NULL)
{
printf("Danh sach rong\n");
return;
}

p=phead;
do
{
p=p->prev;
printf("%d ",p->info);

}
while(p!=phead);

}
void Search(nodeptr phead,int x)
{
nodeptr p;
int vitri=0,found=0;
if(phead==NULL)
{
printf("Danh sach rong\n");
return;
}
p=phead;
do
{
vitri++;
if(p->info==x)
{
printf("Tim thay o vi tri thu %d\n",vitri);
found=1;
}
p=p->next;
}
while(p!=phead);
if(!found)
printf("Khong tim thay\n");
}
void Sort(nodeptr phead)
{
if(phead==NULL)
{
printf("Danh sach rong\n");
return;
}
int temp;
nodeptr p,q;
for(p=phead;p->next!=phead;p=p->next)
for(q=p->next;q!=phead;q=q->next)
if(p->info>q->info)
{
temp=p->info;
p->info=q->info;
q->info=temp;
}
}
void ClearList(nodeptr *phead)
{
nodeptr last,p;
if(*phead==NULL)
{
printf("Danh sach rong\n");
return;
}
last=(*phead)->prev;
while(*phead!=last)
{
p=*phead;
(*phead)=(*phead)->next;
freenode(p);
}
freenode(last);
*phead=NULL;
}

int Count(nodeptr phead)
{
if(phead==NULL)
return 0;
nodeptr last;
int dem=1;
last=phead->prev;
while(phead!=last)
{
dem++;
phead=phead->next;
}
return dem;
}


void InserPrev(nodeptr *phead, int x, int y)
{
   nodeptr tam;
   nodeptr p;
   p= newnode();
   p->info = y;
   if(*phead==NULL)
   {
      *phead=p;
      p->prev=*phead;
      p->next=*phead;
   }
   else
   
   {
      tam=*phead;
      do
      {
         tam= tam->next;
      }
      while(&tam!=phead && tam->info !=x);
      if (tam==*phead)
         {InsertFirst(phead,y);}
      else
      {
         tam->prev->next=p;
         p->prev = tam->prev;
         p->next = tam;
         tam->prev = p;
      }
   }
}
void InserNext(nodeptr *phead, int x, int y)
{
   nodeptr tam;
   nodeptr p;
   p= newnode();
   p->info = y;
   if(*phead==NULL)
   {
      *phead=p;
      p->prev=*phead;
      p->next=*phead;
   }
   else
   
   {
      tam=*phead;
      do
      {
         tam= tam->next;
      }
      while (&tam->next != phead && tam->info !=x);
   }
   if ( tam == (*phead)->prev)
   {InserLast(phead,y);}
   else
   {
      p->next = tam->next;
      (tam->next)->prev = p;
      tam->next=p;
      p->prev = tam;         
   }
}



void DeletePrev(nodeptr *phead, int x)
{
   nodeptr p,tam;
   
   if(*phead==NULL)
   {
      printf("Danh sach rong\n");
      return;
   }
   else if((*phead)->next==(*phead))
   {
      printf("lam gi co nut nao o truoc ma xoa\n");
      return;
   }
   else
   {
      tam=*phead;
      do
      {tam= tam->next;}
      while(&tam!=phead && tam->info !=x);
   }
   if ( tam == *phead)
   {DeleteLast(phead);}
   else
   {
      p = tam->prev;
   //   q= p->prev;
      tam->prev = q;
      p->prev->next = tam;

      free(p);
   
   }
}

void menu()
{
printf("------Menu------\n");
printf("1 - Them 1 nut vao dau danh sach\n");
printf("2 - Them 1 nut vao cuoi danh sach\n");
printf("3 - Hien thi noi dung danh sach\n");
printf("4 - Hien thi noi dung danh sach dao nguoc\n");
printf("5 - Xoa nut dau danh sach\n");
printf("6 - Xoa nut cuoi danh sach\n");
printf("7 - Dem so phan tu cua danh sach\n");
printf("8 - Sap xep danh sach\n");
printf("9 - Tim kiem danh sach\n");
printf("10 - Xoa toan bo danh sach\n");
printf("11 - Them 1 nut vao truoc 1 nut\n");
printf("12 - Them 1 nut vao sau 1 nut\n");
printf("13 - Xoa 1 nut vao truoc 1 nut\n");
printf("0 - Thoat\n");
}
void makemenu()
{
nodeptr head;
Init(&head);
int chucnang,a,b,c;
do
{
printf("Lua chon chuc nang: ");
scanf("%d",&chucnang);
switch(chucnang)
{
case 1:
printf("Nhap gia tri can them: ");
scanf("%d",&a);
InsertFirst(&head,a);
break;
case 2:
printf("Nhap gia tri can them: ");
scanf("%d",&a);
InserLast(&head,a);
break;
case 3:
ShowList(head);
printf("\n");
break;
case 4:
ShowInvert(head);
printf("\n");
break;
case 5:
DeleteFirst(&head);
break;
case 6:
DeleteLast(&head);
break;
case 7:
printf("So phan tu cua danh sach = %d\n",Count(head));
break;
case 8:
Sort(head);
break;
case 9:
printf("Nhap vao gia tri can tim: ");
scanf("%d",&a);
Search(head,a);
break;
case 10:
ClearList(&head);
printf("Da xoa toan bo danh sach\n");
break;
case 11:
printf("Nhap vao gia tri cua nut lam moc: ");
scanf("%d",&b);
printf("Nhap vao gia tri nut them vao: ");
scanf("%d",&c);
InserPrev(&head,b,c);
break;
case 12:
printf("Nhap vao gia tri cua nut lam moc: ");
scanf("%d",&b);
printf("Nhap vao gia tri nut them vao: ");
scanf("%d",&c);
InserNext(&head,b,c);
break;
case 13:
printf("Nhap vao gia tri cua nut lam moc: ");
scanf("%d",&b);
DeletePrev(&head,b);
break;
}
}
while(chucnang!=0);
}
main()
{
menu();
makemenu();
}