void stack_init(stack *stack)
{
	stack->top=0;
}
bool stack_empty(stack *stack)
{
		return (stack->top==0)? true : false;
}
void push(stack *stack,int value)
{
	if(stack->top < MAX_STACK_SIZE-1)
	{
		stack->top++;
		stack->data[stack->top]=value;
	}
	else
	{
		printf("Overflow\n");
	}
}
int pop(stack *stack)
{
	if(stack->top>0)
	{
		stack->top--;
		return stack->data[stack->top+1];
	}
	else
	{
		printf("Underflow\n");
	}
}