void insertBeforeCurrent(ListRef L, long data){ //inserts new node before current
if(!offEnd(L)){ //pre: !offEnd
NodeRef newnode = malloc(sizeof(NodeType));
newnode->data = data;
newnode->count = 1;
newnode->next = NULL;
newnode->prev = NULL;
if(isEmpty(L)){ //checks if list is empty
L->first = newnode;
L->last = newnode;
L->current = newnode;
}else if (atFirst(L)){
newnode->next = L->first;
L->first->prev = newnode;
L->first = newnode;
L->current = newnode;
}else{ //otherwise connects node to list
newnode->next = L->current;
newnode->prev = L->current->prev;
L->current->prev->next = newnode;
L->current->prev = newnode;
}
L->length++;
assert(!offEnd(L) && !isEmpty(L)); //post: !offEnd() and !isEmpty()
}
}
void deleteCurrent(ListRef L){ //deletes current node and frees it
if(!isEmpty(L) && !offEnd(L)){ //pre: !isEmpty() and !offEnd()
if(atLast(L))
deleteLast(L);
else if(atFirst(L))
deleteFirst(L);
else{
NodeRef oldnode = L->current;
L->current->prev->next = L->current->next;
L->current->next->prev = L->current->prev;
L->current = L->current->next;
free(oldnode);
oldnode = NULL;
L->length--;
}
}
}
void deleteFirst(ListRef L){ //deletes first node and frees it
if(!isEmpty(L)){ //pre: !isEmpty()
NodeRef oldnode = L->first;
if(L->first == L->last){ //checks if list is only a single node
L->first = NULL;
L->last = NULL;
L->current = NULL;
}else{
if(atFirst(L))
L->current = L->current->next;
L->first = L->first->next;
L->first->prev = NULL;
}
free(oldnode);
oldnode = NULL;
L->length--;
}
}
/*
* insert before the current node, if defined
*/
void insertBeforeCurrent(ListRef L, long data)
{
NodeRef n;
if (L == NULL) {
printf( "Error: Called insertBeforeCurrent() on NULL ListRef\n");
//exit(EXIT_FAILURE);
} else if (isEmpty(L)) {
printf( "Error: Called insertBeforeCurrent() on empty ListRef\n");
//exit(EXIT_FAILURE);
} else if (offEnd(L)) {
printf("Error: Called insertBeforeCurrent() with offEnd() == true\n");
//exit(EXIT_FAILURE);
}
if (atFirst(L)) {
insertBeforeFirst(L, data);
} else {
n = newNode(data);
n->next = L->current;
n->prev = L->current->prev;
n->prev->next = n;
n->next->prev = n;
L->length++;
}
}
int main (){
/***Exercise List constructor***/
ListHndl List;
List = NULL;
List = newList ();
if(List){
printf("List Created\n");
}else{
printf("List Not Created\n");
}
printf("isEmpty %d\n",isEmpty(List)); /*should print 1*/
/***Populate with test data***/
int i;
for(i=0; i<=4; i++){
insertAtFront(List,i);
}
printList(stdout, List);
printf("isEmpty %d\n",isEmpty(List)); /*should print 0*/
int j;
for(j=5; j<=9; j++){
insertAtBack(List,j);
}
printList(stdout, List);
/***Exercise all access functions***/
printf("offEnd %d\n",offEnd(List));/*should print 0*/
printf("atFirst %d\n",atFirst(List));/*should print 0*/
printf("atLast %d\n",atLast(List));/*should print 0*/
printf("getFirst %d\n", getFirst(List));/*should print 4*/
printf("getLast %d\n", getLast(List));/*should print 9*/
printf("getCurrent %d\n", getCurrent(List));/*should print 0*/
/***Exercise all removal manipulation functions***/
deleteLast(List);
printList(stdout, List);
printf("getLast %d\n", getLast(List));/*should print 8*/
deleteFirst(List);
printList(stdout, List);
printf("getFirst \n", getFirst(List));/*should print 3*/
deleteCurrent(List);
printList(stdout, List);
moveLast(List);
printList(stdout, List);
movePrev(List);
printList(stdout, List);
moveNext(List);
printList(stdout, List);
/***Exercise various edge cases***/
makeEmpty(List);
insertAtFront(List, 40);
moveFirst(List);
deleteCurrent(List);
insertAtFront(List, 41);
insertAtBack(List, 42);
moveFirst(List);
insertBeforeCurrent(List, 43);
printList(stdout, List);
/***Exercise List destructors***/
deleteCurrent(List);
printList(stdout, List);
makeEmpty(List);
printf("offEnd %d\n",offEnd(List));/*should print 1*/
freeList(&List);
return(0);
}