Stack.cpp

#include <iostream>
#include <string>

class Stack 
{
private:
	int top;
	int arr[5];

public:
	Stack() {
		top = -1;
		for (int i = 0; i < 5; i++) 
		{
			arr[i] = 0;
		}
	}

	bool isEmpty()
	{
		if (top == -1)
			return true;
		else
			return false;
	}

	bool isFull()
	{
		if (top == 4)
			return true;
		else
			return false;
	}
	
	void push(int val) 
	{
		if (isFull())
		{
			std::cout << "Stack Overflow!" << std::endl;
		}
		else
		{
			top++;
			arr[top] = val;
		}
	}

	int pop()
	{
		if (isEmpty())
		{
			std::cout << "Stack Underflow!" << std::endl;
			return 0;
		}
		else
		{
			int popValue = arr[top];
			arr[top] = 0;
			top--;
			return popValue; 
		}
	}

	int count()
	{
		return(top + 1);
	}

	int peek(int pos) 
	{
		if(isEmpty())
		{
			std::cout << "Stack Underflow!" << std::endl;
			return 0;
		}
		else
		{
			return arr[pos]; 
		}
	}

	void change(int pos, int val)
	{
		arr[pos] = val;
		std::cout << "Value changed at location" << pos << std::endl;
	}

	void display()
	{
		std::cout << "All values in the Stack are " << std::endl;
		for (int i = 4; i >= 0; i--)
		{
			std::cout << arr[i] << std::endl;
		}
	}
};

int main() 
{
	Stack s1;
	int option, position, value;

	do
	{
		std::cout << "What operation do you want to perform? Select Option number. Enter 0 to exit" << std::endl;
		std::cout << "1. Push()" << std::endl;
		std::cout << "2. Pop()" << std::endl;
		std::cout << "3. isEmpty()_" << std::endl;
		std::cout << "4. isFull()" << std::endl;
		std::cout << "5. peek()" << std::endl;
		std::cout << "6. count()" << std::endl;
		std::cout << "7. change()" << std::endl;
		std::cout << "8. display()" << std::endl;
		std::cout << "9. Clear Screen" << std::endl;

		std::cin >> option;
		switch (option)
		{
		case 1: 
			std::cout << "Enter an item to push in the stack" << std::endl;
			std::cin >> value;
			s1.push(value);
			break;
		case 2:
			std::cout << "Pop function called - Popped Value: " << s1.pop() << std::endl;
			break;
		case 3:
			if (s1.isEmpty())
				std::cout << "Stack is empty" << std::endl;
			else
				std::cout << "Stack is not empty" << std::endl;
			break;
		case 4:
			if(s1.isFull())
				std::cout << "Stack is full" << std::endl;
			else
				std::cout << "Stack is not full" << std::endl;
			break;
		case 5:
			std::cout << "Enter position of item you want to peek: " << std::endl;
			std::cin >> position;
			std::cout << "Peek function called - Value at position " << position << "is " << s1.peek(position) << std::endl;
			break;
		case 6:
			std::cout << "Count function called - Number of items in the stack are: " << s1.count() << std::endl;
			break;
		case 7:
			std::cout << "Change function called - " << std::endl;
			std::cout << "Enter position of item you want to change : ";
			std::cin >> position;
			std::cout << std::endl;
			std::cout << "Enter value of item you want to change : ";
			std::cin >> value;
			s1.change(position, value);
			break;
		case 8:
			std::cout << "Display function called" << std::endl;
			s1.display();
			break;
		case 9: 
			system("cls");
			break;
		default: 
			std::cout << "Enter proper option number " << std::endl;
		}


	} while (option !=0);

	return 0;
}