Main idea LL(1) Parsing uses an explicit stack rather than recursive calls to perform a parse An example: – a simple grammar for the strings of balanced parentheses: S→(S) S∣ε The following table shows the actions of a top￾down parser given this grammar and the string ( )

The memory of a typical computer: A register area; Addressable Random access memory (RAM): A code area; A data area. The code area is fixed prior to execution, and can be visualized as follows:

Attributes – Any property of a programming language construct such as The data type of a variable The value of an expression The location of a variable in memory

Function of a Parser Takes the sequence of tokens produced by the scanner as its input and produces the syntax tree as its output. Parser Sequence of tokens Syntax-Tree

The Function of a Scanner Reading characters from the source code and form them into logical units called tokens Tokens are logical entities defined as an enumerated type – Typedef enum {IF, THEN, ELSE, PLUS, MINUS, NUM, ID,…} TokenType;

一、 单选题 1、试图编译下面的代码块，将会出现什么结果？ public class Test { static int x; public static void main(String args[]){ System.out.println(\Value is \ + x);

图层是用户组织和管理图形的强有力工具。在中文版AutoCAD 2007中， 所有图形对象都具有图层、颜色、线型和线宽这4个基本属性。用户可以使用 不同的图层、不同的颜色、不同的线型和线宽绘制不同的对象和元素，方便控 制了对象的显示和编辑，从而提高绘制复杂图形的效率和准确性

一、开始使用 MATLAB 二、在命令行进行计算 三、MATLAB的帮助功能 四、MATLAB桌面 五、矩阵计算 六、矩阵索引 七、数据类型的使用 八、建立和使用脚本文件

例一 与、或和非逻辑 例二 起动、保持和停止逻辑

1.格式 工矿产品购销合同 供方： 合同编号： 需方： 签订地点： 签订时间： 年 月 日 一、产品名称、商标、型号、厂家、数量、金额、供货时间及数量