Stack in C++ Using Linked List

Here you will learn about stack in C++ using a program example.

Stack is an abstract datatype which follows Last In First Out (LIFO) principle. Basically stack has two operations namely push and pop. 

push: inserting an element at the top of the stack

pop: removing an element from the top of the stack

Below code shows you how to implement stack in C++ using linked list data structure.

Program for Stack in C++

#include<iostream>
#include<process.h>

using namespace std;

struct Node
{
	int data;
	Node *next;
}*top=NULL,*p;

Node* newnode(int x)
{
	p=new Node;
	p->data=x;
	p->next=NULL;
	return(p);
}

void push(Node *q)
{
	if(top==NULL)
		top=q;
	else
	{
		q->next=top;
		top=q;
	}
}

void pop(){
	if(top==NULL){
		cout<<"Stack is empty!!";
	}
	else{
		cout<<"Deleted element is "<<top->data;
		p=top;
		top=top->next;
		delete(p);
	}
}

void showstack()
{
	Node *q;
	q=top;

	if(top==NULL){
		cout<<"Stack is empty!!";
	}
	else{
		while(q!=NULL)
		{
			cout<<q->data<<" ";
			q=q->next;
		}		
	}
}

int main()
{
	int ch,x;
	Node *nptr;
	
	while(1)
	{
		cout<<"\n\n1.Push\n2.Pop\n3.Display\n4.Exit";
		cout<<"\nEnter your choice(1-4):";
		cin>>ch;
		
		switch(ch){
			case 1: cout<<"\nEnter data:";
					cin>>x;
					nptr=newnode(x);
					push(nptr);
					break;
			
			case 2: pop();
					break;
					
			case 3: showstack();
					break;
			
			case 4: exit(0);
			
			default: cout<<"\nWrong choice!!";
		}
	}
	
	return 0;
}

Output:

1.Push
2.Pop
3.Display
4.Exit
Enter your choice(1-4):1

Enter data:7
1.Push
2.Pop
3.Display
4.Exit
Enter your choice(1-4):1

Enter data:8
1.Push
2.Pop
3.Display
4.Exit
Enter your choice(1-4):3
8 7

1.Push
2.Pop
3.Display
4.Exit
Enter your choice(1-4):4