FLEX (Fast Lexical Analyzer Generator) is a tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C around 1987. Lex reads an input stream specifying the lexical analyzer and outputs source code implementing the lexer in the C programming language. The function yylex() is the main flex function which runs the Rule Section.
Prerequisite: FLEX (Fast Lexical Analyzer Generator)
Input: hello how are you? Output: hellohowareyou? Input: Welcome to Geeks for Geeks Output: WelcometoGeeksforGeeks
Open input file in read mode and whenever parser encounters newline (\n), space ( ) or tab (\t) remove it and write all the other characters in output file.
Input File: Input.txt (Input File used in this program)
Below is the implementation program: