#include<iostream>
#include<conio.h>
using namespace std;

int size=0;

class Student{
    public:
        string name;
        int marks;
        Student *nextStudent;
        void setName(string setn){
            name=setn;
        }
        string getName(){
            return name;
        }
        void setMarks(int setm){
            marks=setm;
        }
        int getMarks(){
            return marks;
        }
        void setNextStudent(Student *setAddress){
            nextStudent=setAddress;
        }
        Student* getNextStudent(){
            return nextStudent;
        }
};
class Stack{
    public:
        Student *headStudent=NULL;
        bool isEmpty(){
            if(headStudent==NULL){
                cout<<endl<<"Stack is Empty"<<endl;
                return true;
            }
            else{
                return false;
            }
        }
        void push(){
            string n;
            int m;
            Student *newNode=new Student;
            cout<<"Enter the Name of Student: ";
            cin>>n;
            newNode->setName(n);
            cout<<"Enter the Marks of Student: ";
            cin>>m;
            newNode->setMarks(m);
            newNode->setNextStudent(NULL);
            if(headStudent==NULL){
                headStudent=newNode;
            }
            else{
                Student *ptr=headStudent;
                while ( ptr-> getNextStudent()!=NULL )
                {
                    ptr=ptr->getNextStudent();
                }
                ptr->setNextStudent(newNode);
                
            }

            cout<<endl<<"Student Data saved successfully:";
            size++;
        }
        void pop(){
            if(!isEmpty()){
                Student *pre=headStudent;
                Student *ptr=headStudent;
                while (ptr->getNextStudent()!=NULL)
                {
                    pre=ptr;
                    ptr=ptr->getNextStudent();
                }
                if(ptr==headStudent){
                    headStudent==NULL;
                }
                else{
                    pre->setNextStudent(NULL);
                }
                delete ptr;
                size--;
                cout<<endl<<"Student Data Remove Successfully from database:"<<endl;
            }
        }
        void display(){
            if(!isEmpty()){
                string n[size];
                int m[size],i=0,j=0;
                cout<<"@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"<<endl<<endl;
                cout<<"The Data of All students: "<<endl;
                cout<<"Name\t\tMarks"<<endl;
                Student *ptr=headStudent;
                while(ptr != NULL)
                {
                    n[i++]=ptr->getName();
                    m[j++]=ptr->getMarks();
                    ptr=ptr->getNextStudent();
                }
                for(int k=size-1;k>=0;k--){
                    cout<<n[k]<<"\t\t"<<m[k]<<endl;
                }
                cout<<"@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"<<endl<<endl<<endl;
            }
        }

        void shortStack() {
            for(int i=0;i<size;i++)
			{
                Student *ptr=headStudent;
                for(int j=0;j<size-1;j++)
				{
                    string tmp;
                    if(ptr->getMarks()<ptr->getNextStudent()->getMarks()){
                        
                    }
                    ptr=ptr->getNextStudent();
                }
            }
        }

        void top(){
            if(!isEmpty())
			{
                
                cout<<endl<<endl<<"Top Positions:"<<endl;
                cout<<endl<<"Name\t\tMarks";
                Student *ptr=headStudent;
                for(int k=0;k<3;k++){
                    cout<<endl<<ptr->getName()<<"\t\t"<<ptr->getMarks();
                    ptr=ptr->getNextStudent();
                }
                cout<<endl<<endl;
            }
        }
};
int main()
{
	 Stack s;
	 while(true)
	 {
		 int choice;
		 cout<<endl<<"@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"<<endl<<endl;
		 cout<<" 1.	To add a student in Stack:"<<endl;
		 cout<<" 2.	To remove a Student from Stack"<<endl;
		 cout<<" 3.	Display all students of Stack. :"<<endl;
		 cout<<" 4.	Display top 3 positions of students. "<<endl;
		 cout<<" 5.	Press 5 or any other key to close the program."<<endl<<endl;
		 cout<<"@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"<<endl<<endl<<endl;
		 cout<<"Enter Your Choice (1 ,2, 3, 4, 5):"<<endl;
		 cin>>choice;
		 switch(choice)
		 {
			 case 1:
			 s.push();
			 break;
			 case 2:
			 s.pop();
			 break;
			 case 3:
			 s.display();
			 break;
			 case 4:
			 s.top();
			 break;
			 
			 default :
			 exit(0);
			 break;
		 }
	 }
	 return 0;
}