nt) ==> int, 即去掉整数两边的括号后再归约.
                        operatorStack.pop();
                        calculate(operandStack, operatorStack);
                    }else{
                        calculate(operandStack, operatorStack);
                        operatorStack.pop();
                    }
                    break;
                case ''-'':
                case ''+'':
                    if(!operatorStack.isEmpty()){
                        temp = operatorStack.peek();
                        if(temp->type == ''+'' || temp->type == ''-''){
                            calculate(operandStack, operatorStack);
                        }
                    }
                    operatorStack.push(t);
                    break;
                default:
                    operatorStack.push(t);
                    break;
            }
        }
    }