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

Basic antenna operation Receiving and transmitting antennas are identical: Time just flows in opposite directions. Antenna problems are solved knowing the current distribution J(x') in the antenna and using a vector potential

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 ( )

Why Compiler Writing machine language-numeric codes is time consuming and tedious

5-1 MCS-51单片机最小系统 5-2 存储器的扩展 5-4 可编程并行接口芯片8255A 5-6 常用通道配置与接口技术 5-7 D / A转换 5-3 并行I / O端口的扩展方法 5-5 可编程并行接口芯片8155 5-8 A / D转换

1. Intel 8255A是一个通用的可编程的并行接口芯片，内部有2个8位I/O口（A、B），两个4位I/O口（PC7～4、PC3～0）. 2. 通过编程可设置3种工作方式，可适用于CPU与I/O设备之间的多种数据传送方式的要求

5-1 MCS-51单片机最小系统 5-2 存储器的扩展 5-4 可编程并行接口芯片8255A 5-6 常用通道配置与接口技术 5-7 D / A转换 5-3 并行I / O端口的扩展方法 5-5 可编程并行接口芯片8155 5-8 A / D转换

Elasticity . . . … is a measure of how much buyers and sellers respond to changes in market conditions … allows us to analyze supply and demand with greater precision

In a free, unregulated market system, market forces establish equilibrium prices and exchange quantities. While equilibrium conditions may be efficient, it may be true that not everyone is satisfied

The Law of Supply: uFirms are willing to produce and sell a greater quantity of a good when the price of the good is high. uThis results in a supply curve that slopes upward