C++ Stack Exercises: Delete all occurrences of an item in a stack

C++ Stack: Exercise-13 with Solution

Write a C++ program to delete all occurrences of an item in a stack using arrays.

Test Data:
Input some elements onto the stack:
Stack elements are: 5 2 2 4 7
Remove 2 from the said stack:
Stack elements are: 5 4 7

Sample Solution:

C++ Code:

#include <iostream>

using namespace std;
#define MAX_SIZE 15 // Maximum size of stack

class Stack {
private:
    int top; // Index of top element
    int arr[MAX_SIZE]; // Array to store elements
public:
    Stack() {
        top = -1; // Initialize top index to -1 (empty stack)
    }

    bool push(int x) {
        if (isFull()) {
            cout << "Stack overflow" << endl;
            return false;
        }
        // Increment top index and add element to array
        arr[++top] = x; 
        return true;
    }
    int pop() {
        if (isEmpty()) {
            cout << "Stack underflow" << endl;
            return 0;
        }
        // Return top element and decrement top index
        return arr[top--]; 
    }

    int peek() {
        if (isEmpty()) {
            cout << "Stack is empty" << endl;
            return 0;
        }
        // Return top element without modifying top index
        return arr[top]; 
    }

    bool isEmpty() {
    	// Stack is empty if top index is -1
        return (top < 0); 
    }

    bool isFull() {
    	// Stack is full if top index is equal to MAX_SIZE - 1
        return (top >= MAX_SIZE - 1); 
    }

    void display() {
        if (top < 0) {
            cout << "Stack is empty" << endl;
            return;
        }
        cout << "\nStack elements are: ";
        for (int i = top; i >= 0; i--)
            cout << arr[i] << " ";
        cout << endl;
    }
  void delete_specific_element(Stack& stk, int element) {
    if (stk.isEmpty()) {
        cout << "Stack is empty." << endl;
        return;
    }

    int size = stk.top + 1;
    int temp[size];
    int count = 0;

    // Copy stack elements into a temporary array
    while (!stk.isEmpty()) {
        int current = stk.pop();
        if (current != element) {
            temp[count++] = current;
        }
    }
    // Push non-matching elements back onto the stack
    for (int i = count-1; i >= 0; i--) {
        stk.push(temp[i]);
    }
  }
};
 

int main() {
    Stack stk; 
    cout << "Input some elements onto the stack:";
    stk.push(7);
    stk.push(4);
    stk.push(2);
    stk.push(2);
    stk.push(5);
    stk.display();
    cout << "\nRemove 2 from the said stack:";
    stk.delete_specific_element(stk, 2);
    stk.display();
    cout << "\nInput two more elements onto the stack:";
    stk.push(7);
    stk.push(5);
    stk.display();
    cout << "\nRemove 7 from the said stack:";
    stk.delete_specific_element(stk, 7);
    stk.display();
    cout << endl;
}

Sample Output:

Input some elements onto the stack:
Stack elements are: 5 2 2 4 7

Remove 2 from the said stack:
Stack elements are: 5 4 7

Input two more elements onto the stack:
Stack elements are: 5 7 5 4 7

Remove 7 from the said stack:
Stack elements are: 5 5 4

Flowchart:

CPP Code Editor:

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