private int assignValue(T item)
	{
		int value;
		switch((String)item)
		{
			case "+":
				value = 1;
				break;
			case "-":
				value = 1;
				break;
			case "/":
				value = 2;
				break;
			case "*":
				value = 2;
				break;
			default:
				value = 0;
		}
		return value;
	}