Algorithm for Deletion at Last Node of the Linked LIst

Delete End(info,next,start)

1.if(start=NULL)

   Print Underflow and Exit.

2.if(next[start]==NULL)

   Set ptr =start and start=NULL.

set temp = info[ptr].

else cptr = start and ptr = next[start].

Repeat steps(a) and (b) while(next[ptr]!=NULL)

	(a) set cptr = ptr 

	(b) set ptr = next[ptr]

	[end while]

set next[cptr] = NULL 

	temp = info[ptr]

   [end if]

3. free(ptr)

4. return temp

5. exit	

Fuction of Deletion at the Last of Linked list

void deleteatlast(node **start)

{ 

	node *ptr,*cptr;

	int temp;

	if((*start)->next == NULL)

	{ 

		ptr = *start ;

		*start = NULL;

		temp = ptr->info;

	}

	else

	{ 

		cptr = *start ;

		ptr =(*start)->next;

		while(ptr->next != NULL)

		{ 

			cptr = ptr;

			ptr = ptr->next;

		}

		cptr->next = NULL;

		temp = ptr->info;

	}

	free(ptr);

	printf("\nDeleted item is %d : \n",temp);

}

Deletion at the Last of Linked list

#include<stdio.h>

#include<conio.h>

#include<malloc.h>

typedef struct nodetype

{ int info;

  struct nodetype *next;

} node ;

void createlist(node **,int );

void deleteatlast(node **);

void display(node *);

void main()

{

	node *start;

	int item,n,i;

	clrscr();

	start=NULL;

	printf("Enter no. of nodes :\n");

	scanf("%d",&n);

	for(i= 0 ;i< n ;i++)

	{

		printf("Item for node %d :\n",i+1);

		scanf("%d",&item);

		createlist(&start,item) ;

	}

	printf("The list is :\n");

	display(start);

	printf("\nPress any key to delete last node");

	getch();

	deleteatlast(&start);

	printf("\nThe list after the deletion at first is :\n");

	display(start);

	getch();

}

void createlist(node **start,int item)

{ 

	node *ptr,*last;

	ptr =(node*)malloc(sizeof(node));

	ptr->info = item ;

	ptr->next = NULL;

	if(*start == NULL)

	*start = ptr ;

	else

	{

		last = *start ;

		while(last->next !=NULL)

		{  

			last = last->next;

		}

		last->next = ptr ;

	}

}

void deleteatlast(node **start)

{ 

	node *ptr,*cptr;

	int temp;

	if((*start)->next == NULL)

	{ 

		ptr = *start ;

		*start = NULL;

		temp = ptr->info;

	}

	else

	{ 

		cptr = *start ;

		ptr =(*start)->next;

		while(ptr->next != NULL)

		{ 

			cptr = ptr;

			ptr = ptr->next;

		}

		cptr->next = NULL;

		temp = ptr->info;

	}

	free(ptr);

	printf("\nDeleted item is %d : \n",temp);

}

void display(node *start)

{   int n = 0;

     while(start !=NULL)

     { printf("\t %d",start->info);

       n++;

       start = start->next;

     }

     printf("\n Total number of nodes : %d",n);

}

Output