Write a program to maintain a
link list.
#include <stdio.h>
#include <stdlib.h>
struct node
{
int data ;
struct node * link ;
} ;
void append ( struct node **, int
) ;
void addatbeg ( struct node **,
int ) ;
void addafter ( struct node *,
int, int ) ;
void display ( struct node * ) ;
int count ( struct node * ) ;
void del ( struct node **, int )
;
int main( )
{
struct node *p ;
p = NULL ;
printf ( "\nNo. of elements
in the Linked List = %d", count ( p ) ) ;
append ( &p, 14 ) ;
append ( &p, 30 ) ;
append ( &p, 25 ) ;
append ( &p, 42 ) ;
append ( &p, 17 ) ;
display ( p ) ;
addatbeg ( &p, 999 ) ;
addatbeg ( &p, 888 ) ;
addatbeg ( &p, 777 ) ;
display ( p ) ;
addafter ( p, 7, 0 ) ;
addafter ( p, 2, 1 ) ;
addafter ( p, 5, 99 ) ;
display ( p ) ;
printf ( "\nNo. of elements
in the Linked List = %d", count ( p ) ) ;
del ( &p, 99 ) ;
del ( &p, 1 ) ;
del ( &p, 10 ) ;
display ( p ) ;
printf ( "\nNo. of elements
in the Linked List = %d", count ( p ) ) ;
}
void append ( struct node **q,
int num )
{
struct node *temp, *r ;
if ( *q == NULL )
{
temp = (struct node*)malloc (
sizeof ( struct node ) ) ;
temp -> data = num ;
temp -> link = NULL ;
*q = temp ;
}
else
{
temp = *q ;
while ( temp -> link != NULL )
temp = temp -> link ;
r =(struct node*) malloc ( sizeof
( struct node ) ) ;
r -> data = num ;
r -> link = NULL ;
temp -> link = r ;
}
}
void addatbeg ( struct node **q,
int num )
{
struct node *temp ;
temp = (struct node*)malloc (
sizeof ( struct node ) ) ;
temp -> data = num ;
temp -> link = *q ;
*q = temp ;
}
void addafter ( struct node *q,
int loc, int num )
{
struct node *temp, *r ;
int i ;
temp = q ;
for ( i = 0 ; i < loc ; i++ )
{
temp = temp -> link ;
if ( temp == NULL )
{
printf ( "\nThere are less
than %d elements in list", loc ) ;
return ;
}
}
r = (struct node*)malloc ( sizeof
( struct node ) ) ;
r -> data = num ;
r -> link = temp -> link ;
temp -> link = r ;
}
void display ( struct node *q )
{
printf ( "\n" ) ;
while ( q != NULL )
{
printf ( "%d ", q ->
data ) ;
q = q -> link ;
}
}
int count ( struct node * q )
{
int c = 0 ;
while ( q != NULL )
{
q = q -> link ;
c++ ;
}
return c ;
}
void del ( struct node **q, int
num )
{
struct node *old, *temp ;
temp = *q ;
while ( temp != NULL )
{
if ( temp -> data == num )
{
if ( temp == *q )
*q = temp -> link ;
else
old -> link = temp -> link
;
free ( temp ) ;
return ;
}
else
{
old = temp ; /* old points to the previous node */
temp = temp -> link ; /* go to the next node */
}
}
printf ( "\nElement %d not
found", num ) ;
}
Output
