Thread: 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;
	}
}