#include <iostream>
using namespace std;
#include <string>
 
 
// ------------- STRUCTURE -----------------------------
struct Patient_record // the basic building block of a linked list
{
	int ID;
	string name;
	int age;
	int glucose;
	struct Patient_record* next;
};
 
typedef struct Patient_record* recordptr;  
// define the type of the pointer to a node
 
// ---------- CLASS DEFINITION -----------------------------
class List
{
private:
	recordptr head;  // the head pointer of the linked list
public:
	List();
	~List();
	bool IsListEmpty();
	int Length();
	bool ListInsert(int ID);
	bool ListDelete(int ID);
	recordptr ListRetrieve(int ID);
	void PrintList();
	void ListAvg();
	void ListMax();
	void ListMin();
};
 
// ---------- CONSTRUCTOR ----------------------------
List::List():head(NULL)
{
} 
 
bool List::IsListEmpty()
{
return(head == NULL);
} 
 
// ---------- DESTRUCTOR ----------------------------
List::~List()
{
recordptr temp = head;
while (temp!=NULL)
{
  head = temp->next;
  temp->next = NULL;
  delete temp;
  temp = head;
  }
head = NULL;
} 
 
// ---------- FUNCTION Length ----------------------------
int List::Length()
{
recordptr temp = head;
int counter=0;
while (temp!=NULL)
  {
  counter++;
  temp=temp->next;
  }
return (counter);
} 
 
// ---------- FUNCTION ListInsert for adding patients ----------------
bool List::ListInsert(int patientID)
{ // start function 
recordptr temp = new (struct Patient_record);
if (temp==NULL)
  { 
  cout << "Not enough memory!" << endl;
  return(0);
  } 
else
  {
	temp->ID=patientID;
	temp->next=head;
	head=temp;
 
	cout<<"Enter name of patient: ";
    cin>>temp->name;
    cout<<"Enter age: ";
    cin>>temp->age;
    cout<<"Enter fasting blood glucose: ";
    cin>>temp->glucose;
	cout <<"\n\n";
 
  return (1);
  } 
} 
 
// ---------- FUNCTION PrintList --------------------------
void List::PrintList()
{
recordptr temp = head;
cout << "\n\n*******************" << endl;
cout << " List of patients:" << endl;
cout << "*******************" << endl;
while (temp!=NULL)
  {
	cout << "Patient ID: " << temp->ID << endl;
	cout << "Name      : " << temp->name << endl;
	cout << "Age       : " << temp->age << endl;
	cout << "Glucose   : " << temp->glucose << "\n\n";
 
	temp=temp->next;
}
}
 
// ---------- FUNCTION ListMax -------------------------
void List::ListMax()
{
  recordptr temp = head;
  int max=0;
 
  if(temp!=NULL)
	  max = temp->age;
  temp = temp->next;
 
  while (temp!=NULL)
    {
	  max = (max > temp->age)?max:temp->age;
     temp = temp->next;  
  }
 
  cout << "Highest age: " << max << "\n";
//  while (temp->age==max) I have tried adding this but it only 
// gives me errors when I run the program
//	  cout << "The age is : " << temp->age;
  }

int main()
{
List l;
for(int i=0; i<3; i++)
  l.ListInsert(i);
 
l.PrintList();
l.ListMax(); // invoke to check for minimum value for first print of list 
return 0;
}

void List::ListMax()
{
    recordptr temp = head;
    recordptr max = head;
    int maxAge = 0;
 
    if(temp!=NULL)
        maxAge = temp->age;
 
    temp = temp->next;
 
    while (temp!=NULL)
    {
        if ( temp->age > maxAge)
        {
            maxAge = temp->age;
            max = temp;
        }
        temp = temp->next;  
    }
    if ( max != NULL )
        cout << max->age;
}