C++ Stack Exercises: Implement a stack using a Deque with push, pop operations

Last update on December 20 2024 12:32:03 (UTC/GMT +8 hours)

Write a C++ program to implement a stack using a Deque with push and pop operations. Check if the stack is empty or not and find the top element of the stack.

Test Data:
Initialize a stack using deque:
Is the stack empty? Yes
Input some elements onto the stack:
Deque elements are: 1 5 3 4 2
Top element is 2

Sample Solution:

C++ Code:

#include <iostream>
#include <deque>

using namespace std;

class Stack {
private:
    deque<int> elements; // Deque to store elements

public:
    // Function to add an element to the stack
    void push(int element) {
        elements.push_back(element); // Add element to deque
    }

    // Function to remove an element from the stack
    void pop() {
        if (elements.empty()) {
            cout << "Stack underflow" << endl; // Display underflow message if deque is empty
        } else {
            elements.pop_back(); // Remove last element from deque
        }
    }

    // Function to get the top element of the stack
    int top() {
        if (elements.empty()) {
            cout << "Stack is empty" << endl; // Display empty message if deque is empty
            return 0;
        } else {
            return elements.back(); // Return last element in deque
        }
    }

    // Function to check if the stack is empty
    bool empty() {
        return elements.empty(); // Check if deque is empty
    }

    // Function to display the elements in the stack
    void display() {
        deque<int> d = elements;
        if (d.empty()) {
            cout << "Deque is empty" << endl; // Display empty message if deque is empty
            return;
        }
        cout << "Deque elements are: ";
        for (int i = 0; i < d.size(); i++) {
            cout << d[i] << " "; // Display the elements in the deque
        }
        cout << endl;
    }
};

int main() {
    Stack stack;
    cout << "Initialize a stack using deque:\n"; // Initialize a stack
    cout << "Is the stack empty? " << (stack.empty() ? "Yes" : "No") << endl;
    cout << "\nInput some elements onto the stack:" << endl;
    stack.push(1);
    stack.push(5);
    stack.push(3);
    stack.push(4);
    stack.push(2);
    stack.display();
    cout << "Top element is " << stack.top() << endl;
    cout << "\nRemove two elements from the stack:" << endl;
    stack.pop();
    stack.pop();
    stack.display();
    cout << "Top element is " << stack.top() << endl;
    cout << "\nInput two more elements onto the stack:" << endl;
    stack.push(8);
    stack.push(9);
    stack.display();
    cout << "Top element is " << stack.top() << endl;
    return 0;
}

Sample Output:

Initialize a stack using deque:
Is the stack empty? Yes

Input some elements onto the stack:
Deque elements are: 1 5 3 4 2 
Top element is 2

Remove two elements from the stack:
Deque elements are: 1 5 3 
Top element is 3

Input two more elements onto the stack:
Deque elements are: 1 5 3 8 9 
Top element is 9

Flowchart:

CPP Code Editor:

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Previous C++ Exercise: Find the middle element(s) of a stack (using a vector).
Next C++ Exercise: Sort the stack (using a Deque) elements.