basic operations on liststructure
liststructurepointer next(p)
/* Returns a copy of the link field
value of record pointed to by p.
*/
liststructurepointer p;
{
return(p->link);
}
liststructurepointer sublist(p)
/* Returns a copy of the sublistpointer
field value of record pointed to by p.
*/
liststructurepointer p;
{
return(p->sublistptr);
}
liststructurepointer setnull()
/* Returns a null pointer */
{
return(NULL);
}
liststructurepointer avail()
/* Returns a pointer to storage allocated
for a liststructure record of type
examplerecord.
*/
{
return(malloc(sizeof(examplerecord)));
}
complex(p)
/* Returns true only if the record pointed
to by p is complex.
*/
liststructurepointer p;
{
return(p->kind == 1);
}
createrecord(l,ptr)
/* Reads in the data for the current record
and sets its fields appropriately.
*/
liststructurepointer 1,ptr;
{
int link,subptr,value,kind;
liststructurepointer setnull(),avail();
printf("\n enter info \n");
scanf("%d",&value);
printf("\n enter 0 for simple 1
for complex \n");
scanf("%d",&kind);
if (kind == 0)
{
printf("\n enter link \n");
scanf("%d",&link);
if (link == 0)
ptr->link = setnull();
else
ptr->link = avail();
}
else
{
printf("\n enter link & subptr \n");
scanf("%d %d",&link,&subptr);
if (link == 0)
ptr->link = setnull();
else
ptr->link = avail();
if (subptr == 0)
ptr->sublistptr = setnull();
else
ptr->sublistptr = avail();
}
ptr->info = value;
ptr->kind = kind:
}
printrecord(pls,ptr)
/* Prints the contents of the info field
of the record pointed to by ptr.
*/
liststructurepointer *pls,ptr;
{
printf("\n %d \n",ptr->info);
}