Lex

Lex compiler is a tool widely used to specify lexical analyzers for a variety of languages. We refer to the tool as Lex compiler,and to its input specification as the Lex language. Lex allows one to specify a lexical analyzer by specifying regular expressions to describe patterns for tokens.
This document gives a brief description about lexical compiler, its syntax, structure and general functions and variables used in it.
The theory part is followed by a set of programs based on LEX.The document consists of the following programs:


1)Program to count the number of vowels, consonants, characters, words, spaces and lines in a given text file.

2)Program to count number of
i) Positive and negative integers
ii) Positive and negative fractions

3)Program to count the numbers of comment lines in a syntactically correct C or C++ program

4)Program to count the number of ‘scanf’ and ‘printf’ statements in a syntactically correct C program ).

5) Program to recognize a valid simple arithmetic expression and identify the operands

6)Program to recognize whether a given English sentence is simple or compound

7)Program to recognize the preprocessor statements (only #include and #define) in a syntactically correct C program

8)Write a program to recognize static words(is,am,was etc) from english.

Please seed after download.