Sorting a Lnked List by readjusting links in C

#include <stdio.h>
#include <conio.h>
#include <malloc.h>
/* structure containing a data part and link part */
struct node
{
 int data ;
 struct node *link ;
} *start, *visit ;
void getdata( ) ;
void append ( struct node **q, int num ) ;
void displaylist( ) ;
void selection_sort( ) ;
void bubble_sort( ) ;
int main( )
{
 getdata( ) ;
 printf ( "Linked List Before Sorting:\n" ) ;
 displaylist( ) ;
 selection_sort( ) ;
 printf ( "Linked List After Selection Sorting:\n" ) ;
 displaylist( ) ;
 getdata( ) ;
 printf ( "Linked List Before Sorting:\n" ) ;
 displaylist( ) ;
 bubble_sort( ) ;
 printf ( "Linked List After Bubble Sorting:\n" ) ;
 displaylist( ) ;
 return 0 ;
}
void getdata( )
{
 int val ;
 char ch ;
 struct node *newnode;
 newnode = NULL ;
 do
 {
  printf ( "Enter a value: " ) ;
  scanf ( "%d", &val ) ;
  append ( &newnode, val ) ;
  printf ( "Any More Nodes (Y/N): " ) ;
  fflush ( stdin ) ;
  ch = getchar( ) ;
  printf ( "\n" ) ;
 } while ( ch == 'y' || ch == 'Y' ) ;
 start = newnode ;
}
/* 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 = ( struct node * ) 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 = ( struct node * ) 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 ;
 }
 printf ( "\n" ) ;
}
void selection_sort( )
{
 struct node *p, *q, *r, *s, *temp ;
 p = r = start ;
 while ( p -> link != NULL )
 {
  s = q = p -> link ;
  while ( q != NULL )
  {
   if ( p -> data > q -> data )
   {
    if ( p -> link == q )  /* Adjacent Nodes */
    {
     if ( p == start )
     {
      p -> link = q -> link ;
      q -> link = p ;
      temp = p ;
      p = q ;
      q = temp ;
      start = p ;
      r = p ;
      s = q ;
      q = q -> link ;
     }
     else
     {
      p -> link = q -> link ;
      q -> link = p ;
      r -> link = q ;
      temp = p ;
      p = q ;
      q = temp ;
      s = q ;
      q = q -> link ;
     }
    }
    else
    {
     if ( p == start )
     {
      temp = q -> link ;
      q -> link = p -> link ;
      p -> link = temp ;
      s -> link = p ;
      temp = p ;
      p = q ;
      q = temp ;
      s = q ;
      q = q -> link ;
      start = p ;
     }
     else
     {
      temp = q -> link ;
      q -> link = p -> link ;
      p -> link = temp ;
      r -> link = q ;
      s -> link = p ;
      temp = p ;
      p = q ;
      q = temp ;
      s = q ;
      q = q -> link ;
     }
    }
   }
   else
   {
    s = q ;
    q = q -> link ;
   }
  }
  r = p ;
  p = p -> link ;
 }
}
void bubble_sort( )
{
 struct node *p, *q, *r, *s, *temp ;
 s = NULL ;
 /* r precedes p and s points to the node up to which comparisons are to
     be made */
 while ( s != start -> link )
 {
  r = p = start ;
  q = p -> link ;
  while ( p != s )
  {
   if ( p -> data > q -> data )
   {
    if ( p == start )
    {
     temp = q -> link ;
     q -> link = p ;
     p -> link = temp ;
     start = q ;
     r = q ;
    }
    else
    {
     temp = q -> link ;
     q -> link = p ;
     p -> link = temp ;
     r -> link = q ;
     r = q ;
    }
   }
   else
   {
    r = p ;
    p = p -> link ;
   }
   q = p -> link ;
   if ( q == s )
    s = p ;
  }
 }
}