#include<stdio.h>
#include<stdlib.h>
struct node
{
	int data;
	struct node *address;
};
struct node *createnode(int item)
{
	struct node *p;
	p=(struct node *)malloc(sizeof(struct node));
	p->data=item;
	p->address=NULL;
	return p;
};
struct node *insertbeg(struct node *n,struct node *head)
{
	if(head==NULL)
	{
		head=n;
	}
	else
	{
		n->address=head;
		head=n;
		return head;
	}
};
struct node *insertmid(struct node *n,struct node *head,int pos)
{
	int i;
	struct node *p;
	i=1;
	p=head;
	while(p->address!=NULL&&i<pos-1)
	{
		p=p->address;
		i++;
	}
	n->address=p->address;
	p->address=n;
};
struct node *insertend(struct node *n,struct node *head)
{
	struct node *p;
	if(head==NULL)
	{
		head=n;
	}
	else
	{
		p=head;
		while(p->address!=NULL)
		{
			p=p->address;
		}
		p->address=n;
	}
	return head;
};
struct node *delbeg(struct node *head)
{
	if(head==NULL)
	{
		printf("empty");
	}
	else
	{
		head=head->address;
	}
	return head;
};
struct node *delmid(struct node *head,int data)
	{
	if(head==NULL)
	{
		printf("empty");
	}
	else
	{
		struct node *c,*p;
		c=p=head;
		while(p->data!=data&&p!=NULL)
		{
			c=p;
			p=p->address;
		}
		if(p!=NULL)
		{
			c->address=p->address;
		}
		else
		{
			printf("no data found");
		}
	}
};
struct node *delend(struct node *head)
{
	struct node *p,*c;
	if(head==NULL)
	{
		printf("empty");
	}
	else
	{
		c=p=head;
		while(p->address!=NULL)
		{
			c=p;
			p=p->address;
		}
		c->address=NULL;
	}
	return head;
};
void traversal(struct node *head);
void main()
{
int choice,a,po;
struct node *head=NULL,*p;
while(1)
{
printf("\nenter the choice :\n 1.insert at the begining \n2.insert at a position\n3.insert at the end\n4.delete at the begining \n5.delete at a position \n6.delete at the end	\n7.trversal\n");
scanf("%d",&choice);
switch(choice)
{
case 1:
{
printf("you are at option 1.insert at the begining\n");
printf("enter the data\n");
scanf("%d",&a);
p=createnode(a);
head=insertbeg(p,head);
break;
}
case 2:
{
printf("you are at choice 2.insert at a position\n");
printf("enter the data\n");
scanf("%d",&a);
printf("enter the position to be inserted");
scanf("%d",&po);
p=createnode(a);
head=insertmid(p,head,po);
break;
}
case 3:
{
printf("you are at choice 3.insert at the end\n");
printf("enter the data\n");
scanf("%d",&a);
p=createnode(a);
head=insertend(p,head);
break;
}
case 4:
{
printf("you are at choice 4.delete at the begining");
head=delbeg(head);
break;
}
case 5:
{
printf("you are at choice 5.delete at a position");
printf("enter the data");
scanf("%d",&a);
head=delmid(head,a);
break;
}
case 6:
{
printf("you are at choice 6.delete at the end");
head=delend(head);
break;
}
case 7:
{
printf("you are at choice 7.trversal\n");
struct node *p;
if(head==NULL)
{
printf("empty");
}
else
{
p=head;
while(p!=NULL)
{
printf("%d\n",p->data);
p=p->address;
}
}
break;
}
default:
{
printf("you have entered the wrong option ");
break;
}
}
}
}