double ONP()
	{
	char c;
	StackItem* pHead = NULL; // wyzerowanie stosu
	DStackItem* pDHead = NULL; // wyzerowanie stosu

	dpush(&pDHead, GetNum());
	while (IsOper(c=GetOper()))
	{
		if (c == '(')
		{
			push(&pHead, c); // dopisuje na stos nawias otwierający
			dpush(&pDHead, GetNum());
		}
		else if (c == ')')
		{
			while (c != '(')
			{
				while (prior(c) <= prior(top(pHead)))
				{
					double x = dpop(&pDHead);
					dpush(&pDHead, Eval(pop(&pHead), dpop(&pDHead), x));
				}
				break;
			}
			pop(&pHead);
		}
		else
		{
			while (prior(c) <= prior(top(pHead))) // prior operatora MUSI byc silnie wiekszy od prior szczytu stosu
			{
				double x = dpop(&pDHead);
				dpush(&pDHead, Eval(pop(&pHead), dpop(&pDHead), x)); // podmianka
			}
			push(&pHead, c);
			if (IsOper(c == GetOper()))
				ungetc(c, stdin);
			else
			{
				ungetc(c, stdin);
				dpush(&pDHead, GetNum());
			}
		}
	}
	while (!isEmpty(pHead))
	{
		double x = dpop(&pDHead);
		dpush(&pDHead, Eval(pop(&pHead), dpop(&pDHead), x));
	}
	return dpop(&pDHead);
}