C++ Stack Exercises: Find and remove the largest element in a stack

C++ Stack: Exercise-10 with Solution

Write a C++ program to find and remove the largest element in a stack.

Test Data:
Input some elements onto the stack:
Stack elements are: 5 2 4 7
Find and remove the largest element 7 from the stack.
Stack elements are: 5 2 4

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;
  }
  
int find_and_Remove_max_val() {
    if (isEmpty()) {
        cout << "Stack is empty" << endl;
        return -1;
    }

    int maxElement = INT_MIN;
    Stack temp;
    while (!isEmpty()) {
        int element = pop();
        if (element > maxElement) {
        	//If a larger element is found, update maxElement
            maxElement = element; 
        }
        // Add other elements to the temporary stack
        temp.push(element);  
    }

    while (!temp.isEmpty()) {
        int element = temp.pop();
        // All elements except the largest are pushed back onto the stack
        if (element != maxElement) {  
            push(element);
        }
    }
    return maxElement;
}

};

int main() {
         //Initialize the stack stk
   Stack stk;
   cout << "Input some elements onto the stack:";
   stk.push(7);
   stk.push(4);
   stk.push(2);
   stk.push(5);
   stk.display();
   int z = stk.find_and_Remove_max_val();
   cout << "Find and remove the largest element " << z << " from the stack.";
   stk.display();
   cout << "\nInput two more elements";
   stk.push(-1);
   stk.push(20);
   stk.display();
   z = stk.find_and_Remove_max_val();
   cout << "Find and remove the largest element " << z << " from the stack.";
   stk.display();
         cout << endl;
   return 0;
}

Sample Output:

Input some elements onto the stack:
Stack elements are: 5 2 4 7
Find and remove the largest element 7 from the stack.
Stack elements are: 5 2 4

Input two more elements
Stack elements are: 20 -1 5 2 4
Find and remove the largest element 20 from the stack.
Stack elements are: -1 5 2 4

Flowchart:

CPP Code Editor:

Contribute your code and comments through Disqus.

Previous C++ Exercise: Find the middle element of a stack (using an array).
Next C++ Exercise: Find and remove the lowest element in a stack.