C Program to Implement Doubly Linked List Operations

struct Node;
typedef struct Node * PtrToNode;
typedef PtrToNode List;
typedef PtrToNode Position;

struct Node
{
int e;
Position previous;
Position next;
};

void Insert(int x, List l, Position p)
{
Position TmpCell;
TmpCell = (struct Node*) malloc(sizeof(struct Node));
if(TmpCell == NULL)
printf(“Memory out of space\n”);
else
{
TmpCell->e = x;
TmpCell->previous = p;
TmpCell->next = p->next;
p->next = TmpCell;
}
}

int isLast(Position p)
{
return (p->next == NULL);
}

Position Find(int x, List l)
{
Position p = l->next;
while(p != NULL && p->e != x)
p = p->next;
return p;
}

void Delete(int x, List l)
{
Position p, p1, p2;
p = Find(x, l);
if(p != NULL)
{
p1 = p -> previous;
p2 = p -> next;
p1 -> next = p -> next;
if(p2 != NULL) // if the node is not the last node
p2 -> previous = p -> previous;
}
else
printf(“Element does not exist!!!\n”);
}

void Display(List l)
{
printf(“The list element are :: “);
Position p = l->next;
while(p != NULL)
{
printf(“%d -> “, p->e);
p = p->next;
}
}

void main()
{
int x, pos, ch, i;
List l, l1;
l = (struct Node *) malloc(sizeof(struct Node));
l->previous = NULL;
l->next = NULL;
List p = l;
printf(“DOUBLY LINKED LIST IMPLEMENTATION OF LIST ADT\n\n”);
do
{
printf(“\n\n1. INSERT\t 2. DELETE\t 3. FIND\t 4. PRINT\t 5. QUIT\n\nEnter the choice :: “);
scanf(“%d”, &ch);
switch(ch)
{
case 1:
p = l;
printf(“Enter the element to be inserted :: “);
scanf(“%d”,&x);
printf(“Enter the position of the element :: “);
scanf(“%d”,&pos);
for(i = 1; i < pos; i++) { p = p->next;
}
Insert(x,l,p);
break;

    case 2:
        p = l;
        printf("Enter the element to be deleted :: ");
        scanf("%d",&x);
        Delete(x,p);
        break;

    case 3:
        p = l;
        printf("Enter the element to be searched :: ");
        scanf("%d",&x);
        p = Find(x,p);
        if(p == NULL)
            printf("Element does not exist!!!\n");
        else
            printf("Element exist!!!\n");
        break;

    case 4:
        Display(l);
        break;
    }
}
while(ch<5);

}

OUTPUT:
DOUBLY LINKED LIST IMPLEMENTATION OF LIST ADT

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice :: 1
Enter the element to be inserted :: 10
Enter the position of the element :: 1

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice :: 1
Enter the element to be inserted :: 20
Enter the position of the element :: 2

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice :: 1
Enter the element to be inserted :: 30
Enter the position of the element :: 3

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice :: 4
The list element are :: 10 -> 20 -> 30 ->

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice :: 3
Enter the element to be searched :: 20
Element exist!!!

1. INSERT 2. DELETE 3. FIND 4. PRINT 5. QUIT

Enter the choice ::