Doubly Linked List

[kim6987]

can you please spend a little time evaluating this code.
I can not run it successfully
thanks :)

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#define SIZE 10
 
typedef struct dlist
{
 int val;
 struct dlist *next,*prev;
}*dll;
//---------------- FUNCTION SEARCH_VAL --------------------------------------
dll search_val(dll head,int data)
{
 dll temp;
 temp=head;
 while(temp)
   {
    if(temp->val==data)
      return(1);
    else
      temp=temp->next;
   }
  return(0);
}
//---------------- FUNCTION ADD_BEG -----------------------------------------
void add_beg(dll head,dll n_new)
{
 dll temp;
 temp=head;
 while(temp->prev!=NULL)
     temp=temp->prev;
 
 n_new->next=temp->next;
 temp->next->prev=n_new;
 temp->next=n_new;
 n_new->prev=temp;
}
//---------------- FUNCTION ADD_END  ----------------------------------------
void add_end(dll head,dll n_new)
{
 dll temp;
 temp=head;
 while(temp->next!=NULL)
   temp=temp->next;
 temp->next=n_new;
 n_new->prev=temp;
 n_new->next=NULL;
}
//---------------- FUNCTION DELETE ------------------------------------------
int delete(dll head,int data)
{
 dll temp;
 temp=head;
 while(temp)
  {
   if(temp->val==data)
    {
     temp->prev->next=temp->next;
     temp->next->prev=temp->prev;
     temp->prev=temp->next->next;
     return(temp->val);
    }
  else
   temp=temp->next;
  }
 
 return(NULL);
}
//---------------- FUNCTION DISPLAY  ----------------------------------------
void display(dll head)
{
 dll temp;
 printf("\n\n\t THE DOUBLY LINKED LIST IS ::");
 printf("HEAD->");
 temp=head->next;
 while(temp)
  {
   printf("<-%d->",temp->val);
   temp=temp->next;
  }
 printf("NULL");
}
//---------------- FUNCTION GET_NODE-----------------------------------------
dll get_node()
{
 dll n_new;
 n_new=malloc(sizeof(struct dlist));
 printf("\n\n\t ENTER THE VALUE ::");
 scanf("%d",&n_new->val);
 n_new->next=NULL;
 n_new->prev=NULL;
 return(n_new);
}
//---------------- FUNCTION CREATE ------------------------------------------
dll create()
{
 dll head,n_new,last;
 char c;
 head=malloc(sizeof(struct dlist));
 head->next=NULL;
 head->prev=NULL;
 last=head;
 do
 {
  n_new=malloc(sizeof(struct dlist));
  printf("\n\n\t ENTER THE VALUE ::");
  scanf("%d",&n_new->val);
  last->next=n_new;
  n_new->prev=last;
  n_new->next=NULL;
  last=n_new;
  printf("\n\n\t CREATE ANY MORE NODE (Y/N) ::");
  c=getche();
 }while(c=='y'||c=='Y');
 
 return(head);
}
//--------------------------------------------------------------------------
void main()
{
 dll head,n_new;
 int choice,data;
 char c;
// textcolor(14);
 while(1)
 {
 //clrscr();
 printf("\n\n\t THE DOUBLY LINKED LIST OPERATION :: ");
 printf("\n\n\t 1> CREATE LIST");
 printf("\n\n\t 2> DISPLAY");
 printf("\n\n\t 3> ADD AT END");
 printf("\n\n\t 4> ADD AT BEGINING");
 printf("\n\n\t 5> SEARCH");
 printf("\n\n\t 6> DELETE");
 printf("\n\n\t 7> EXIT");
 printf("\n\n\t ENTER YOUR CHOICE ::");
 scanf("%d",&choice);
 switch(choice)
  {
   case 1:head=create();
          display(head);
          break;
   case 2:display(head);
          break;
   case 3:new=get_node();
          add_end(head,n_new);
          display(head);
          break;
   case 4:n_new=get_node();
          add_beg(head,n_new);
          display(head);
          break;
   case 5:printf("\n\n\t ENTER THE VALUE TO BE SEARCHED :: ");
          scanf("%d",&data);
          if(search_val(head,data))
            {
             printf("\n\n\t THE VALUE IS PRESENT IN THE LIST ");
             display(head);
            }
          else
            {
             printf("\n\n\t THE VALUE IS NOT PRESENT IN THE LIST ");
             display(head);
            }
          break;
   case 6:printf("\n\n\t ENTER THE VALUE TO BE DELETED ::");
          scanf("%d",&data);
          if(search_val(head,data))
            {
             data=delete(head,data);
             printf("\n\n\t THE DATA DELETED FROM THE LIST IS :: %d",data);
             display(head);
            }
          else
            {
              if(head->next==NULL)
                {
                 printf("\n\n\t THE LIST IS EMPTY ");
                 display(head);
                }
              else
               {
                printf("\n\n\t THE DATA IS NOT PRESENT IN THE LIST ");
                display(head);
               }
            }
          break;
   case 7:printf("\n\n\t PRESS ESC TO EXIT ");
          if(getch()==27)
            exit(0);
          break;
 
  }
 
  getch();
 }
}
//--------------------------------------------------------------------------*/
 

here are the error info. in Dev C
In function `dlist* search_val(dlist*, int)':
19 .invalid conversion from `int' to `dlist*'
19 At global scope:
50 expected unqualified-id before "delete"
......

[Ganon11]

dll search_val(dll head,int data)
{
 dll temp;
 temp=head;
 while(temp)
   {
    if(temp->val==data)
      return(1);
    else
      temp=temp->next;
   }
  return(0);
}

Your function header says this returns a dll, but you only return 0 or 1.

[kim6987]

oh , thanks.
one more please :)
after I fix that one , anothers occur :


In function `int n_delete(dlist*, int)':
67 [Warning] converting to non-pointer type `int' from NULL
In function `dlist* get_node()':
87 invalid conversion from `void*' to `dlist*'

[Ganon11]

In the first case, you are now doing to opposite thing - returning NULL, which only has meaning when used with pointers, when your function promises an int return value.

In the second case, you are using malloc, but not casting the result to anything. malloc returns a void*, and you need a dll*.

Have you tried reading your errors? They provide the line of code where the error/warning occurs, and usually give an accurate description of what's going on. All I've done is look at the line number, go to that spot, and see another simple mistake. You can do the exact same thing without me, I'm sure.

[kim6987]

hi Ganon11 !

after reading your suggestion then I 've corrected them
about Null : I just ignore it . :)

// return(NULL);

about malloc

it now is

n_new=(struct dlist*) malloc(sizeof(struct dlist));

that's all I could do.
and then I compiled. It worked :but it run incorrectly with the delete function.( because of the return I ignored ?

definitely I need more reading about C

Thank you for your patience !