//CIS:610-251 Data Structures and Algos
//Assignment # 2 Question # 4
//Stack Operations

#include<iostream.h>

#define STACKSIZE 256

class Stack
{
private:
	int  * data; //data value in stack
	int spMax;   //Max Stack Pointer Value;
public:
	Stack() ;
	Stack(Stack& s);
	Stack(unsigned size); 
	
	void pushandtest(int);
	int popandtest() ;
	void push(int);
	int pop();
	int getTopNth(unsigned);
	int getBottomNth(unsigned);
	int StackTop();
	bool Empty(void);
};

//Constructor
Stack::Stack()
{ 
	data=new int(STACKSIZE); //init data as an array of 256 integer
	spMax=STACKSIZE-1;			
	data[0]=0; //init stack index		
}

//Constructor if size of Stack is given
Stack::Stack(unsigned size)
{ 
	spMax=size;
	data=new int(size+1);
	data[0]=0; //init index
}

//Copy Constructor
Stack::Stack(Stack& s)
{
	int i=1;
	this->spMax=s.spMax;
	this->data=new int[this->spMax+1];
	this->data[0]=s.data[0];
	for(;i<=data[0];i++) this->data[i]=s.data[i];
}

//Add an element to Stack and increment the SP.
void Stack::pushandtest(int item)
{ 
	if (data[0]<spMax) data[++data[0]]=item; 
	else cout << " Overflow";
}

//Add an element to Stack and increment the SP, dont care for overflow
void Stack::push(int item)
{ 
	data[++data[0]]=item; 
}

//Return the Top most element of stack,decrement the SP, dont care for underflow
int Stack::pop()
{ 
	return data[data[0]--]; 
}

//Return the Top most element of stack and decrement the SP
int Stack::popandtest()
{ 
	if (data[0]>0) return data[data[0]--]; 
	else return NULL;
}

//return how many elements in Stack.
int Stack::StackTop()
{
	return data[data[0]];
}

//if Stack Empty return True
bool Stack::Empty()
{
	if (data[0]) return false;else return true;
}



main()
{
Stack main;

main.push(2);
main.push(9);
main.push(7);
main.pushandtest(3);
main.pushandtest(50);
main.pushandtest(44);
main.pushandtest(13);
cout << "\nIs Stack empty: " << main.Empty();
cout << "\nLast in Item: " << main.pop();
cout << "\nStack Top is: " << main.StackTop();
cout << "\nNext POPed is :" << main.popandtest() << '\n';

return 0;

}