Stack.cpp

/**
Program for creating the stack using the linked list.
Program performs all the operations such as push, pop and display.
It takes care of stack underflow condition.
**/

#include <iostream>
#include <stdlib.h>

using namespace std;

// Declaration for data structure  of linked stack
template <class T>
class Lstack {
	private:
	typedef struct stack {
		T data;
		struct stack *next;
	}node;
	node *top, *temp;
	public:
	Lstack() {
		top = NULL;
	}
	
	void push();
	void display();
	void pop();
};

/*push function*/
template <class T>
void Lstack <T> ::push() {
	node *temp = new node;
	temp->next = NULL;
	cout << "Enter the new item:" << endl;
	cin >> temp->data;
	temp -> next = top;
	top = temp;
}
/*pop function*/
template <class T>
void Lstack <T> ::pop() {
	if (top == NULL)
		cout << "No more elements left. Stack underflow." << endl;
	else {
		node *temp = new node;
		cout << "The popped item is: " << top->data << endl;
		temp = top;
		top = top -> next;
		delete temp;
	}
}
/*display function*/
template <class T>
void Lstack <T> ::display() {
	if (top == NULL)
		cout << "The stack is empty.";
	else {
		node *temp = new node;
		temp = top;
		cout << "Stack display:" << endl;
		while (temp != NULL) {
			cout << " " << temp->data;
			temp = temp->next;
		}
	}
	cout << endl;
}
/*main*/
void main() {
	int choice;
	char ans = 'y';
	Lstack <int> stack;
	cout << "Stack using Linked List" << endl;
	while(ans == 'y') {
		cout << "Main menu" << endl;
		cout << "1. push\n2. pop\n3. display" << endl;
		cout << "Enter your choice:" << endl;
		cin >> choice;
		switch(choice) {
			case 1: stack.push(); break;
			case 2: stack.pop(); break;
			case 3: stack.display(); break;
			default: exit(0);
		}
		cout << "Do you want to continue? y/n" << endl;
		cin >> ans;
	}
}