Bubble sorting singly link list

Hello All,

Following is the bubble sorting program. It is crashing is sort function. Please let me know, where I;m goig wrong.

Code:

# include <stdio.h>
# include <stdlib.h>

void append(struct node **,struct node *);
void display(struct node *);
int Delete_nth_node(struct node **,int i);
void sort(struct node **);
void delTree(struct node *);

//struct node *merge_list(struct node **ppHead1,struct node **ppHead2);
//struct node *merge(struct node *current1,struct node *current2);
//int length(struct node *walk);

struct node
{
	int data;
	struct node *next;
}node;

void main(void)
{
	int i, result;
	struct node *pHead1, *new_node;

	pHead1 = NULL;

	printf("Enter the numbers for list 1:\n");
	if ( scanf("%d",&i) == 1 )
	{
		while (i)
		{	
			new_node = calloc(1,sizeof(node));
			new_node->data = i;
			append(&pHead1,new_node);
			if ( scanf("%d",&i) == 1 )
				continue;
			else
				break;
		}
		display(pHead1);
	}

//	printf("\nAfter deleting 2nd node\n");
	
//	result = Delete_nth_node(&pHead1,2);
//	if ( result )
//		display(pHead1);

	sort(&pHead1);
	display(pHead1);

	delTree(pHead1);
}

void sort(struct node **ppHead)
{
	struct node *current,*forward,*save;

	current = *ppHead;
	forward = current->next;
	save = NULL;

	while(current)
	{
		while(forward)
		{
			if (current->data > forward->data)
			{
				struct node *temp;
				temp = forward->next;
				forward->next = current;
				current->next = temp;
				forward = temp;
				if (save)
					save->next = current;
			}
			else
				forward = forward->next;
		}
		save = current;
		current = current->next;
		forward = current->next;
	}
}


// Inserts, appends or prepends depending upon its value.
void append(struct node **ppHead, struct node *new_node)
{
	struct node *current;

	// First time when not even single node is generated
	if ( *ppHead == NULL )
	{
		new_node->next = NULL;
		*ppHead = new_node;
	}
	else 
	{
		current = *ppHead;
		
		while (current->next != NULL)
			current = current->next;
		
		current->next = new_node;
	}
}


int Delete_nth_node(struct node **ppHead,int i)
{
	struct node *current,*nth_node,*save;

	nth_node = NULL;
	current = *ppHead;

	while ( current )
	{
		if ( current == NULL && (!nth_node) )
			return 0;
		else if ( !i )
		{
			save = nth_node = *ppHead;

			while (1)
			{
				if ( current->next == NULL )
					break;
				current = current->next;
				save = nth_node;
				nth_node = nth_node->next;
			}
			if ( save == nth_node)
			{
				*ppHead = save->next;
				return 1;
			}
			save->next = nth_node->next;
			free(nth_node);
			return 1;
		}
		current = current->next;
		i--;
	}
	return 0;
}

// Displays entire link list
void display(struct node *walk)
{
	printf("\nLink list is:\n");
	while (walk)
	{
		printf("%d\t",walk->data);
		walk = walk->next;
	}
}

void delTree(struct node *walk)
{
	struct node *save;
	while (walk)
	{
		save = walk->next;
		free(walk);
		walk = save;
	}
}

This is where I find pencil and paper very handy. I draw little boxes on the paper representing the nodes with an arrow pointing from each box to the one after it, creating the list. Then I walk through each step in the sorting routine one at a time in my head and draw what the list would look like after moving one node. Then just keep repeating that process until you find the reason the routine is blowing up on you

>Bubble sorting singly link list
Why are you trying to bubble sort anything to begin with? Insertion sort is easier to code and faster than bubble sort for linked lists.