ADT Stack

[ArtisticMess]

Im trying to learn about stacks as an abstract data type creating my own. my code complies but im getting a logical error when displayed I keep getting a 12 or some random number im thinking there is a problem with my printStack function with displaying the copy of the stack from the for loop

#include<iostream>
using namespace std;

class Stack
{
public:
	Stack()
	{
		items = 0;
		count = 0;
	}
	bool isEmpty() // returns true if stack is empty
	{
		return count == 0;
	}
	bool isFull()// return true if stack is full
	{
		return count == 8;
	}
	void push(int n)// item n is pushed onto stack, throw exception on full stack.
	{
		if (isFull())
		{
			throw "The Stack Is Full";
		}
		newItem = newItem & 0x0F;
		items = items << 4;
		items = items | newItem;
		count++;
	}
	void pop() // removes top item from stack, throw exception on empty stack.
	{
		if (isEmpty())
		{
			throw "The Stack Is Empty";
		}
		else items = items >> 4;
	    count--;
	}
	int top() // returns top of stack, throw exception on empty stack.
	{
		if (isEmpty())
		{
			throw "The Stack Is Empty";
		}
		return items & 0x0F;
	}
	void printStack() // prints stack, stack is unchanged
	{
		unsigned int copy = items;

		for (int i=0; i < count; i++)
		{
			cout << (copy & 0x0F);
			copy = copy >> 4;
		}

	}
private:
	unsigned int newItem;
	unsigned int items;
	int count;
	int copy;
 


};

#include<iostream>
#include"stack.h"
using namespace std;


int main()
{
	Stack strange;
	int choice = 1;
	int num = 0;
	
	cout << " Strange stack " << endl;
	
	while(choice!=0)
	{
		
		cout << " 1=Push	2=Pop	3=Top	0=Quit " << endl;
		cin >> choice;
		try{
			if (choice == 1)
			{
				cout << " Enter A Number 0-15 "<<endl;
				cin >> num;
				if (num>15||num<0)
				{
					num = 0;
				}
				strange.push(num);
				strange.printStack();
			}
			if (choice == 2)
			{
				strange.top();
			 cout << " number popped " << num << endl;
			 strange.pop();
			 strange.printStack();
			}
			if (choice == 3)
			{
				strange.top();
			}
		}
		catch (char* str)
		{
			cout << str;
		}
		if (choice == 0)
		{
			cout << "Bye" << endl;
			return 0;
		}
	}

[kbw]

Have you learned of arrays? You must have, because you're using a class.

Anyway, it's conventional to use an array to hold the elements. You seem to be doing some weird shift thing. You're not storing bits your storing ints.

[ArtisticMess]

now I'm kind of confused sorry so I need to create an array to hold the values of the user number inputs and cycle through them in the for loop

[ArtisticMess]

I'm not suppose to use an array now I'm completely lost

[sylphsang]

via link list u can do

[coder777]

There is a warning on line 26:

warning: 'strange.Stack::newItem' may be used uninitialized in this function

in push() you do not use n at all.

[ArtisticMess]

I was just looking at that lol. I changed it to

 void push(newItem)// item n is pushed onto stack, throw exception on full stack.
	{
		if (isFull())
		{
			throw "The Stack Is Full";
		}
		newItem = newItem & 0x0F;
		items = items << 4;
		items = items | newItem;
		count++;
	}
	void pop() // removes top item from stack, throw exception on empty stack.
	{
		if (isEmpty())
		{
			throw "The Stack Is Empty";
		}
		else items = items >> 4;
	    count--;} 

but now im getting a logic error with my pop function when I push 321 on to the stack and I pop it off 3 times it just says 1 was popped off instead of popped number 1 popped number 2 popped number 3

[coder777]

On line 34 you show num which is irrelevant. Change lines 33/34:

cout << " number popped " << strange.top()<< endl;

[stilts9119]

I believe Line 1 of your corrected code ArtisticMess should be the following instead

void push(int newItem)// item n is pushed onto stack, throw exception on full stack.
	{
		if (isFull())
		{
			throw "The Stack Is Full";
		}
		newItem = newItem & 0x0F;
		items = items << 4;
		items = items | newItem;
		count++;