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class LList
{
private:
//a Food struct stores info for a food
struct Food
{
string name, group;
float cal, per;
Food* next;
Food()
{
name="nothing";
group="nothing";
cal=0;
per=0;
next=NULL;
}
};
public:
typedef Food* FoodPtr;
FoodPtr head, tail, index;
//function prototypes go here
void AddNode(FoodPtr head, FoodPtr tail, FoodPtr index);
FoodPtr PrevNode(FoodPtr index);
void Forward();
void Backward();
void DelNode(FoodPtr index);
FoodPtr NextNode();
FoodPtr PrevNode();
FoodPtr ReadFood(ifstream &inFile);
//constructor
LList();
//destructor
~LList();
//function prototypes end here
};
//////////////////////// FUNCTION DEFINITIONS /////////////////////////
//function definitions go here
void LList::AddNode(FoodPtr head, FoodPtr tail, FoodPtr index)
{
// original
// tail->next= new Food;
// tail=tail->next;
//testing new code
ifstream inFile;
inFile.open("file.txt");
FoodPtr temp;
while ((temp=ReadFood(inFile)))
{
//add Food to list
if (head==NULL)
{
//creates head of list
head=temp;
//node is only one in the list, is both head and tail right now
tail=temp;
}
else
{
//current Food, tail, now references new Food
tail->next=temp;
//new food becomes tail, referenced by previous Food
tail=temp;
}
}
//end of list
index=tail;
tail->next=NULL;
//always close the stream
inFile.close();
}
FoodPtr LList::PrevNode(FoodPtr index)
{
FoodPtr temp=head;
if (index==head) //no previous node, return head
{
return head;
}
while (temp->next!=index)
{
temp=temp->next;
}
return temp;
}
void LList::Forward()
{
if (index->next!=NULL)
{
index=index->next;
}
}
void LList::Backward()
{
if (index!=head)
{
index=PrevNode(index);
}
}
void LList::DelNode(FoodPtr index)
{
FoodPtr deltor=index;
if (index==head) //delete the head
{
head=head->next;
delete deltor;
}
else if (index==tail) //delete the tail
{
tail=PrevNode(index);
tail->next=NULL;
delete deltor;
}
else //delete a middle node
{
index=PrevNode(index);
index->next=deltor->next;
delete deltor;
}
index=head;
}
FoodPtr ReadFood(ifstream &inFile)
{
FoodPtr temp=NULL;
//temp values
string tName, tGroup;
float tCal, tPer;
if (inFile >> tName >> tGroup >> tCal >> tPer)
{
temp=new Food;
//store infor in created object
temp->name=tName;
temp->group=tGroup;
temp->cal=tCal;
temp->per=tPer;
}
return temp;
}
LList::LList()
{
FoodPtr temp;
head=new Food;
tail=head;
temp=head;
}
LList::~LList()
{
FoodPtr temp, deltor;
temp=deltor=head;
while (temp!=NULL)
{
temp=temp->next;
delete deltor;
deltor=temp;
}
}
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