different pointer changes in same code

[fizisyen]

Hi,

My problem is like the below code. In "pushes" function "ptr++" is increasing 16 bytes

and in "pops" "ptr--" code decreasing only 1 byte as normal. I didnt understand the 16.

Why 16 and 1?

(BC++ 5.5)

#include<iostream.h>
#include<stdlib.h>
#include<string.h>
#include <stdio.h>

class stack{
public:
	stack();
	~stack();
	void pushes(char kr);
	void pops();
private:
	char* ptr;
	int tos;
};

stack::stack()
{

	tos = 0;
	ptr = (char*) malloc(sizeof(char));
	if (!ptr)
	{
		cout << "alloc err\n";
		exit(1);
	}
}

stack::~stack()
{
	free(ptr);
}

void stack::pushes(char kr)
{
	ptr = (char*) malloc(sizeof(char));
	if (!ptr)
	{
		cout << "alloc err\n";
		exit(1);
	}
	*ptr = kr;		
	
	tos++;
	ptr++;
//	printf("%d\n",ptr);
}

void stack::pops()
{
	if (tos == 0)
	{
		cout << "stack empty\n";
		return;
	}
	tos--;
//	printf(" - %d\n",ptr);	
	cout << "pushed [" << tos << "] :" << *ptr << endl;
	ptr-= 16;
}

int main()
{
	int i;

	stack pushpop;

	pushpop.pushes('A');
	pushpop.pushes('B');
	pushpop.pushes('C');

	for (i = 0; i < 3; i++)
	{
		pushpop.pops();
	}
	return 0;
}