## Recursive descent parser

### RECURSIVE DESCENT PARSER

A parser that uses collection of recursive procedures for parsing the given input string is called Recursive Descent (RD) Parser.

Basic steps for construction of RD parser:
1. The R.H.S. of the rule is directly converted into program code symbol by symbol.
2. If the input is non-terminal then a call to the procedure corresponding to the non-terminal is made.
3. If the input is terminal then it is matched with the look ahead from input. The look- ahead pointer has to be advanced on matching of the input symbol.
4. If the production rule has many alternates then all these alternates has to be combine into a single body of procedure.
5. The parser should be activated by a procedure corresponding to the start symbol.
Predictive LL (1) parser

This top down parsing algorithm is of non- recursive type. In this type of parsing a table is built. for LL(1):

The first L means the input is scanned from left to right.
The second L means it uses left most derivation for input string. & the number 1 in the input symbol (look-ahead) to predict the parsing process.

The data structure used by LL(1) are:
1. Input Buffer
2. stack
3. parsing table

#### Construction of Predictive LL (1) Parser

This parser is based on two very important function & those are FIRST and FOLLOW.

For construction of predictive LL(1) parser we have to follow the following steps-
1. Computation of FIRST and FOLLOW function.
2. Construct the predictive parsing table using FIRST and FOLLOW functions.
3. Parse the input string with the help of predictive parsing table.

#### FIRST function

Following are the rules used to compute the FIRST functions.
1. If the terminal symbol a the FIRST (a) = {a}.
2. If there is a rule X --> e then FIRST (X) = {e}.
3. For the rule A-->X1 X2 X3 .....Xk FIRST (A) = (FIRST (X1) U FIRST (X2) U FIRST (X3) .... U FIRST (Xk).
Where K Xj <= n such that 1<= j <= k-1.

The rule of computing FOLLOW function are as given below-
1. For the start symbol S place \$ in FOLLOW(S).
2. If there is a production A --> aBb then everything in FIRST(b) without e is to be placed in FOLLOW(B).
3. If there is a production A --> aBb or A --> aB and FIRST (b) ={e} then FOLLOW (A) = FOLLOW(B) or FOLLOW(B) = FOLLOW (A). That means everything in FOLLOW (A) is in FOLLOW (B).
ACA: ADVANCED COMPUTER ARCHITECTURE EasyExamNotes.com covered following topics in these notes.
Discrete Strucutre ↓ 👆
Discrete Structure EasyExamNotes.com covered following topics in these notes.
A list of Video lectures
Information Storage Management ↓ 👆
Network & Web Security ↓ 👆
Web Engineering ↓ 👆
Web Engineering EasyExamNotes.com covered following topics in these notes.
Cloud Computing ↓ 👆

Cloud Computing:

EasyExamNotes.com covered following topics in Cloud Computing.

1. Buyya, Selvi ,” Mastering Cloud Computing “,TMH Pub
2. Krutz , Vines, “Cloud Security “ , Wiley Pub
3. Velte, “Cloud Computing- A Practical Approach” ,TMH Pub
4. Sosinsky, “ Cloud Computing” , Wiley Pub
Python Programming ↓ 👆
Principles of Programming Languages ↓ 👆
Principles of Programming Languages
EasyExamNotes.com covered following topics in these notes.

#### Language Evaluation Criteria Influences on Language Design  Language Categories Programming Paradigms Compilation Virtual Machines  Programming Environments Issues in Language Translation Parse Tree  Pointer and Reference type Concept of Binding Type Checking Strong typing  Sequence control with Expression Subprograms Fundamentals of sub-programs Scope and lifetime of variable Static and dynamic scope Design issues of subprogram and operations Local referencing environments Parameter passing methods Overloaded sub-programs Generic sub-programs  Design issues for functions  Co routines  Abstract Data types Abstraction and encapsulation Static and Stack-Based Storage management Garbage Collection OOP in C++ OOP in Java  OOP in C#  OOP in PHP Concurrency Semaphores  Monitors Message passing Java threads  C# threads  Exception handling  Exceptions Exception Propagation  Exception handler in C++  Exception handler in Java Introduction and overview of Logic programming Basic elements of Prolog Application of Logic programming Functional programming languages Introduction to 4GL  Practicals: Memory Implementation of 2D Array.  Memory Implementation of 3D Array.  Implementation of pointers in C++.  Write a program in Java to implement exception handling. Write a program in C++ to implement call by value parameter passing Method. Write a program in C++ to implement call by reference parameter passing Method.  Write a program in Java to implement concurrent execution of a job using threads. Implement Inheritance in C#. Implement Encapsulation in C#. Implement static/compiletime Polymorphism in C#. Implement dynamic/runtime Polymorphism in C#. Previous years solved papers: PPL|RGPV|May 2018  PPL|RGPV|June 2017  A list of Video lectures Click here References: Sebesta,”Concept of programming Language”, Pearson Edu  Louden, “Programming Languages: Principles & Practices” , Cengage Learning  Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill.  E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

Computer Organization and Architecture ↓ 👆

### Computer Organization and Architecture

#### References:

1. William stalling ,“Computer Architecture and Organization” PHI
2. Morris Mano , “Computer System Organization ”PHI

Theory of Computation ↓ 👆
TOC EasyExamNotes.com covered following topics in these notes.
Computer Network ↓ 👆
Computer Network

EasyExamNotes.com covered following topics in these notes.
References:
1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.
R Programming ↓ 👆

### R Programming

EasyExamNotes.com covered following topics in these notes.

Management Information System ↓ 👆