stack programs in c -2

Question .Write program implements linked list as a stack ?

Ans :

#include 

#include 

#include 



/* structure containing data part and linkpart */

struct node

{

	int data ;

	struct node *link ;

} ;



void push ( struct node **, int ) ;

int pop ( struct node ** ) ;

void delstack ( struct node ** ) ;



void main( )

{

	struct node *s = NULL ;

	int i ;



	clrscr( ) ;



	push ( &s, 14 ) ;

	push ( &s, -3 ) ;

	push ( &s, 18 ) ;

	push ( &s, 29 ) ;

	push ( &s, 31 ) ;

	push ( &s, 16 ) ;



	i = pop ( &s ) ;

	printf ( "\nItem popped: %d", i ) ;



	i = pop ( &s ) ;

	 printf ( "\nItem popped: %d", i ) ;



	i = pop ( &s ) ;

	printf ( "\nItem popped: %d", i ) ;



	delstack ( &s ) ;



	getch( ) ;

}



/* adds a new node to the stack as linked list */

void push ( struct node **top, int item )

{

	struct node *temp ;

	temp = ( struct node * ) malloc ( sizeof ( struct node ) ) ;



	if ( temp == NULL )

		printf ( "\nStack is full." ) ;



	temp -> data = item ;

	temp -> link = *top ;

	*top = temp ;

}



/* pops an element from the stack */

int pop ( struct node **top )

{

	struct node *temp ;

	int item ;



	if ( *top == NULL )

	{

		printf ( "\nStack is empty." ) ;

		return NULL ;

	}



	temp = *top ;

	item = temp -> data ;

	*top = ( *top ) -> link ;



	free ( temp ) ;

	return item ;

}



/* deallocates memory */

void delstack ( struct node **top )

{

	struct node *temp ;



	if ( *top == NULL )

		return ;



	while ( *top != NULL )

	{

		temp = *top ;

		*top = ( *top ) -> link ;

		free ( temp ) ;

	}

}