Linked list implementation of Stack and Queue.

stack-and-queue-using-structure.cpp

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

using namespace std;
 
struct NODE{
	int val;
	struct NODE *next;
};
 
typedef struct NODE node;
 
class stack{
private:
	node *top;
public:
	stack(){
		top = NULL;
	}
	~stack(){
		cout<<"Emptying stack"<<endl;
	}
	void push(int val){
		if(top == NULL){
			top = new node;
			top->val = val;
			return;
		}
		node *temp = new node;
		temp->val = val;
		temp->next = top;
		top = temp;
		cout<<"Pushed "<<top->val<<endl;
	}
	void pop(){
		if(top == NULL){
			cout<<"Stack Underflow - not popped"<<endl;
			return;
		}
		cout<<"Popped "<<top->val<<endl;
		node *temp = top;
		top = top->next;
		delete temp;
	}
	void print(){
		node *temp;
		cout<<"Stack state : ";
		if(top == NULL){
			cout<<"<empty>"<<endl;
			return;
		}
		for(temp = top; temp != NULL; temp = temp->next){
			cout<<temp->val<<" ";
		}
		cout<<endl;
	}
};
 
class queue{
private:
	node *front;
	node *back;
public:
	queue(){
		front = back = NULL;
	}
	~queue(){
		cout<<"Emptying queue"<<endl;
	}
	void push(int val){
		node *temp = new node;
		temp->val = val;
		if(back == NULL)
			back = temp;
		else
			front->next = temp;
		front = temp;
		cout<<"Pushed "<<front->val<<endl;
	}
	void pop(){
		if(back == NULL){
			cout<<"Queue empty - not popped"<<endl;
			return;
		}
		cout<<"Popped "<<back->val<<endl;
		node *temp = back;
		back = back->next;
		delete temp;
	}
	void print(){
		node *temp;
		cout<<"Queue state : ";
		if(back == NULL){
			cout<<"<empty>"<<endl;
			return;
		}
		for(temp = back; temp!= NULL; temp = temp->next){
			cout<<temp->val<<" ";
		}
		cout<<endl;
	}
};
 
int main(){
	int choice;
	stack one;
	queue two;
 
	for(choice=0 ;choice != 4;){
		cout<<"\n1.Push random\n2.Pop\n3.Print\n4.Stop"<<endl;
		cin>>choice;
		switch(choice){
			case 1:
			one.push(rand()%100);
			one.print();
			break;
			case 2:
			one.pop();
			one.print();
			break;
			case 3:
			one.print();
			break;
			case 4:
			break;
			default:
			cout<<"Continue"<<endl;
			break;
		}
	}
 
	for(choice=0 ;choice != 4;){
		cout<<"\n1.Enqueue random\n2.Dequeue\n3.Print\n4.Stop"<<endl;
		cin>>choice;
		switch(choice){
			case 1:
			two.push(rand()%100);
			two.print();
			break;
			case 2:
			two.pop();
			two.print();
			break;
			case 3:
			two.print();
			break;
			case 4:
			break;
			default:
			cout<<"Continue"<<endl;
			break;
		}
	}
 
	return 0;
}