Lex Program to remove comments from C program

Lex is a computer program that generates lexical analyzers. Lex reads an input stream specifying the lexical analyzer and outputs source code implementing the lexer in the C programming language.

The commands for executing the lex program are:

lex abc.l (abc is the file name)
cc lex.yy.c -efl
./a.out

Let’s see LEX program to accept string starting with vowel.
Examples:

Input : 
//testing
#include 
int main()
{
 /* multiline comment
    continue....
 */
 return 0;
}

Output :
#include 
int main()
{
 
 return 0;
}

Below is the implementation:

/% Lex Program to remove comments from C program
   and save it in a file %/
/*Definition Section*/
%{
%}

/*Starting character sequence for multiline comment*/
start \/\*
/*Ending character sequence for multiline comment*/
end  \*\/

/*Rule Section*/
%%

/*Regular expression for single line comment*/
\/\/(.*) ;
/*Regular expression for multi line comment*/
{start}.*{end} ;

%%

/*Driver function*/
int main(int k,char **argcv)
{
yyin=fopen(argcv[1],"r");
yyout=fopen("out.c","w");
/*call the yylex function.*/
yylex();
return 0;
}

Output:

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