Top Operation in Stack

Top operation is used to return the top element of the stack.

Below is a sample program to show Pop operation in Stack.

C++

#include <bits/stdc++.h> 
using namespace std; 

int topElement(stack<int>& s) { return s.top(); } 

int main() 
{ 

    stack<int> s; // creating a stack of integers 

    s.push(1); // This pushes 1 to the stack top 
    cout << topElement(s) 
        << endl; // Prints 1 since 1 is present at the 
                // stack top 

    s.push(2); // This pushes 2 to the stack top 
    cout << topElement(s) 
        << endl; // Prints 2 since 2 is present at the 
                // stack top 

    s.push(3); // This pushes 3 to the stack top 
    cout << topElement(s) 
        << endl; // Prints 3 since 3 is present at the 
                // stack top 
}

Java

import java.util.Stack;

public class StackExample {

    public static int topElement(Stack<Integer> s) {
        return s.peek();
    }

    public static void main(String[] args) {
        Stack<Integer> s = new Stack<>();

        // Pushing 1 to the stack top
        s.push(1);
        System.out.println(topElement(s)); // Prints 1

        // Pushing 2 to the stack top
        s.push(2);
        System.out.println(topElement(s)); // Prints 2

        // Pushing 3 to the stack top
        s.push(3);
        System.out.println(topElement(s)); // Prints 3
    }
}

Python3

# Python code:

def topElement(s):
    return s[-1]

s = [] # creating a stack of integers

s.append(1) # This pushes 1 to the stack top
print(topElement(s)) # Prints 1 since 1 is present at the stack top

s.append(2) # This pushes 2 to the stack top
print(topElement(s)) # Prints 2 since 2 is present at the stack top

s.append(3) # This pushes 3 to the stack top
print(topElement(s)) # Prints 3 since 3 is present at the stack top

# This code is contributed by Sakshi

using System;
using System.Collections.Generic;

class Program
{
    static int TopElement(Stack<int> s)
    {
        return s.Peek();
    }

    static void Main()
    {
        Stack<int> s = new Stack<int>(); // creating a stack of integers

        s.Push(1); // This pushes 1 to the stack top
        Console.WriteLine(TopElement(s)); // Prints 1 since 1 is present at the stack top

        s.Push(2); // This pushes 2 to the stack top
        Console.WriteLine(TopElement(s)); // Prints 2 since 2 is present at the stack top

        s.Push(3); // This pushes 3 to the stack top
        Console.WriteLine(TopElement(s)); // Prints 3 since 3 is present at the stack top
    }
}

Javascript

function topElement(s) {
    return s[s.length - 1];
}

// Main function
function main() {
    let s = []; // Creating an array to act as a stack

    s.push(1); // Pushing 1 to the stack
    console.log(topElement(s)); // Prints 1 since 1 is at the top of the stack

    s.push(2); // Pushing 2 to the stack
    console.log(topElement(s)); // Prints 2 since 2 is at the top of the stack

    s.push(3); // Pushing 3 to the stack
    console.log(topElement(s)); // Prints 3 since 3 is at the top of the stack
}

// Calling the main function
main();
//THis code is contributed by Utkarsh

Output

1
2
3

Basic Operations in Stack Data Structure with Implementations

In order to make manipulations in a stack, there are certain operations provided to us for Stack, which include:

push() to insert an element into the stack
pop() to remove an element from the stack
top() Returns the top element of the stack.
isEmpty() returns true if the stack is empty else false.
size() returns the size of the stack.

In this post, we will see how to perform these operations on Stack.

Tags:

#DSA #Stack #Stack

Pop Operation in Stack:

isEmpty Operation in Stack:

Top Operation in Stack

Basic Operations in Stack Data Structure with Implementations

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