typedef struct treerecord

{

int info;

struct treerecord *leftptr;

struct treerecord *rightptr;

}binarytreerecord,*binarytreepointer;

#define NULL 0

binarytreepointer left(p)

/* Returns a copy of the left

pointer of the node p points to.

*/

binarytreepointer p;

{

return(p->leftptr);

}

binarytreepointer right(p)

/* Returns a copy of the right

pointer of the node p points to.

*/

binarytreepointer p;

{

return(p->rightptr);

}

binarytreepointer setnull()

/* Returns a null pointer */

{

return(NULL);

}

binarytreepointer avail()

/* Returns a pointer to storage

allocated for a new node.

*/

{

return(malloc(sizeof(binarytreerecord)));

}

setinfo(p,pvalue)

/* Copies the contents of value

into the record p points to.

*/

binarytreepointer p;

int *pvalue;

{

p->info = *pvalue;

}

setleft(p,q)

/* Copies q into the left pointer

of the record p points to.

*/

binarytreepointer p,q;

{

p->leftptr = q;

}

setright(p,q)

/* Copies q into the right pointer

of the record p points to.

*/

binarytreepointer p,q;

{

p->rightptr = q;

}

printnode(pl,ptr)

/* Prints the info field of the

record ptr points to.

*/

binarytreepointer *pl,ptr;

{

printf("\n %d",ptr->info);

}