A stack-based environment will result in a dangling reference when the procedure is exited if a local variable in a procedure can be returned to the caller The simplest example:

• 可编程中断控制器8259A的功能 • 8259A的结构 • 8259A的控制字及编程使用

7.1模拟量输入通道 7.2A/D转换接口技术 7.3D/A转换接口技术

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:

7.1模拟量输入通道 7.2A/D转换接口技术 7.3D/A转换接口技术

One parse tree only a The role of the grammar a distinguish between syntactically legal and illegal programs a But that's not enough: it must also define a parse tree a the parse tree conveys the meaning of the program What if a string can be parsed with multiple parse trees? a we say the grammar is ambiguous a must fix the grammar(the problem is not in the parser) a Note: often a string can be derived in more than one way D ie, with more than one derivation sequence o this does not mean the grammar is ambiguous

一、8255A的工作原理 二、8255A的应用举例

理解 A/D 转换的原理与过程 了解 A/D 的基本参数及应用

9-1 8255A的工作原理 9-2 8255A的应用举例

复旦大学：《有机化学A》课程教学资源（学生课件）a,b-不饱和醛酮的还原 Reduction of a,b - unsaturated carbonyl compounds