linkedlistalloperations.c

#include<stdio.h>
#include<conio.h>
#include<malloc.h>
#include<process.h>

/*Structure declaration for the node*/
struct node
{
	int info;
	struct node *link;
}*start;

/*This function will create a new linked list*/
void Create_List(int data)
{
	struct node *q, *tmp;

	/*Dynamic memory is been allocated for a node*/
	tmp= (struct node*)malloc (sizeof (struct node));
	tmp->info=data;
	tmp->link=NULL;
	if (start==NULL) /*If list is empty*/
	start = tmp;
	else
	{ /*Element inserted at the end*/
		q=start;
	    while(q->link!=NULL)
	    	q=q->link;
	    q->link=tmp;
	}
	
}/*End of create_list()*/

/*This function will add new element at the beginning of the linked list*/
void AddAtBeg(int data)
{
	struct node *tmp;
	tmp=(struct node*)malloc(sizeof(struct node));
	tmp->info=data;
	tmp->link=start;
	start=tmp;
}/*End of addatbeg()*/
 
/*Following function will add new element at any position*/
void AddAfter (int data ,int pos)
{
	struct node *tmp,*q;
	int i;
	q=start;
	/*Finding the position to add new element to the linked list*/
	for(i=0;i<pos-1;i++)
	{
		q=q->link;
		if(q==NULL)
		{
			printf ("\n\n There are less than %d elements",pos);
			getch();
			return;
		}
	}/*End of for*/

		tmp=(struct node*)malloc(sizeof (struct node));
		tmp->info=data; 
		tmp->link=q->link;
		q->link=tmp;
}/*End of addafter()*/

/*
     Delete any element from the linked list*/
void Del(int data)
{
	struct node *tmp,*q;
	if (start->info == data)
	{
		tmp=start;
		start=start->link; /*First element deleted*/
		free(tmp);
		return;
	}
	q=start;
	while(q->link->link!= NULL)
	{
	    if(q->link->info == data) /*Element deleted in between*/
	    {
	    	tmp=q->link;
	    	q->link=tmp->link;
	    	free(tmp);
	    	return;
	    }
	    q=q->link;
    }/*End of while */

    if(q->link->info==data) /*Last element deleted*/
	{
    	tmp=q->link;
    	free(tmp);
    	q->link=NULL;
    	return;
    }
    printf ("\n\nElement %d not found",data);
    getch();
    }/*End of del()*/

/*This function will display all the element(s) in the linked list*/
void Display()
{
	struct node *q;
	if(start == NULL)
	{
		printf ("\n\nList is empty");
		return;
	}
	q=start;
	printf("\n\nList is : ");
	while(q!=NULL)
	{
		printf ("%d ", q->info);
		q=q->link;
	}
	printf ("\n");
	getch();
	}/*End of display() */

/*Function to count the number of nodes in the linked list*/
void Count()
{
	struct node *q=start;
	int cnt=0;
	while(q!=NULL)
	{
		q=q->link;
		cnt++;
	}
	printf ("Number of elements are %d\n",cnt);
	getch();
	}/*End of count()*/

/*This function will reverse the linked list*/
void Rev()
{
	struct node *p1,*p2,*p3;
	if(start->link==NULL) /*only one element*/
	return;
	p1=start;
	p2=p1->link;
	p3=p2->link;
	p1->link=NULL;
	p2->link=p1;
	while(p3!=NULL)
	{
		p1=p2;
		p2=p3;
		p3=p3->link;
		p2->link=p1;
	}
	start=p2;
}/*End of rev()*/

/*Function to search an element from the linked list*/
void Search(int data)
{
	struct node *ptr = start;
	int pos = 1;

	/*searching for an element in the linked list*/
	while(ptr!=NULL)
	{
		if (ptr->info==data)
		{
			printf ("\n\nItem %d found at position %d", data, pos);
			getch();
			return;
		}
		ptr = ptr->link;
		pos++;
	}
	if (ptr == NULL)
		printf ("\n\n Item %d not found in list", data);
	getch ();
}

int main()
{
	int choice, n, m, position,i;
	start=NULL;
	while(1)
	{
	/*clrscr();*/
		printf ("1.Create List\n");
		printf ("2.Add at beginning\n");
		printf ("3.Add after \n");
		printf ("4.Delete\n");
		printf ("5.Display\n");
		printf ("6.Count\n");
		printf ("7.Reverse\n");
		printf ("8.Search\n");
		printf ("9.Quit\n");
		printf ("\nEnter your choice:");
		scanf ("%d",&choice);
		switch (choice)
		{
			case 1:
			printf ("\n\nHow many nodes you want:");
			scanf ("%d",&n);
			for(i = 0;i<n;i++)
				{
					printf ("\nEnter the element:");
					scanf ("%d",&m);
					Create_List(m);
				}
			break;

			case 2:
			printf ("\n\nEnter the element : ");
			scanf ("%d",&m);
			AddAtBeg(m);
			break;

			case 3:
			printf ("\n\nEnter the element:");
			scanf ("%d",&m);
			printf ("\nEnter the position after which this element is inserted:");
			scanf ("%d",&position);
			AddAfter(m,position);
			break;

			case 4:
			if (start == NULL)
			{
				printf("\n\nList is empty");
				continue;
			}
			printf ("\n\nEnter the element for deletion:");
			scanf ("%d",&m);
			Del(m);
			break;

			case 5:
			Display();
			break;

			case 6:
			Count();
			break;

			case 7:
			Rev();
			break;

			case 8:
			printf("\n\nEnter the element to be searched:");
			scanf ("%d",&m);
			Search(m);
			break;

			case 9:
			exit(0);

			default:
			printf ("\n\nWrong choice");

			return 0;
		
		}/*End of switch*/
	}/*End of while*/
}/*End of main()*/