Program to sort a linked list by swapping data

/* Program to sort a linked list by swapping data.*/

#include <stdio.h>
#include <conio.h>
#include <alloc.h>

/* structure containing a data part and link part */
struct node
{
int data ;
struct node *link ;
} *newnode, *start, *visit ;

void getdata( ) ;
void append ( struct node **, int ) ;
void displaylist( ) ;
int count ( struct node * ) ;
void selection_sort ( int ) ;
void bubble_sort ( int ) ;

void main( )
{
int n ;

getdata( ) ;

clrscr( ) ;
printf ( "Linked List Before Sorting: " ) ;
displaylist( ) ;

n = count ( start ) ;

selection_sort ( n ) ;
printf ( "\nLinked List After Selection Sorting: " ) ;
displaylist( ) ;
getch( ) ;

getdata( ) ;
clrscr( ) ;
printf ( "Linked List Before Sorting: " ) ;
displaylist( ) ;

n = count ( start ) ;

bubble_sort ( n ) ;
printf ( "\nLinked List After Bubble Sorting: " ) ;
displaylist( ) ;
getch( ) ;
}

void getdata( )
{
int val, n ;
char ch ;
struct node *new ;

clrscr( ) ;

new = NULL ;
do
{
printf ( "\nEnter a value: " ) ;
scanf ( "%d", &val ) ;

append ( &new, val ) ;

printf ( "\nAny More Nodes (Y/N): " ) ;
ch = getche( ) ;
} while ( ch == 'y' || ch == 'Y' ) ;

start = new ;
}

/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
struct node *temp ;
temp = *q ;

if ( *q == NULL ) /* if the list is empty, create first node */
{
*q = malloc ( sizeof ( struct node ) ) ;
temp = *q ;
}
else
{
/* go to last node */
while ( temp -> link != NULL )
temp = temp -> link ;

/* add node at the end */
temp -> link = malloc ( sizeof ( struct node ) ) ;
temp = temp -> link ;
}

/* assign data to the last node */
temp -> data = num ;
temp -> link = NULL ;
}

/* displays the contents of the linked list */
void displaylist( )
{
visit = start ;

/* traverse the entire linked list */
while ( visit != NULL )
{
printf ( "%d ", visit -> data ) ;
visit = visit -> link ;
}
}

/* counts the number of nodes present in the linked list */
int count ( struct node * q )
{
int c = 0 ;

/* traverse the entire linked list */
while ( q != NULL )
{
q = q -> link ;
c++ ;
}

return c ;
}

void selection_sort ( int n )
{
int i, j, k, temp ;
struct node *p, *q ;

p = start ;
for ( i = 0 ; i < n - 1 ; i++ )
{
q = p -> link ;

for ( j = i + 1 ; j < n ; j++ )
{
if ( p -> data > q -> data )
{
temp = p -> data ;
p -> data = q -> data ;
q -> data = temp ;
}
q = q -> link ;
}
p = p -> link ;
}
}

void bubble_sort ( int n )
{
int i, j, k, temp ;
struct node *p, *q ;

k = n ;
for ( i = 0 ; i < n - 1 ; i++, k-- )
{
p = start ;
q = p -> link ;

for ( j = 1 ; j < k ; j++ )
{
if ( p -> data > q -> data )
{
temp = p -> data ;
p -> data = q -> data ;
q -> data = temp ;
}
p = p -> link ;
q = q -> link ;
}
}
}