Gtu Ez: Implement following programs using Lex. a. Write a Lex program to print out all numbers from the given file. b. Write a Lex program to printout all HTML tags in file. c. Write a Lex program which adds line numbers to the given file and display the same onto the standard output.

a. Write a Lex program to print out all numbers from the given file.

lex file: a.l

%{
    intpostiveno=0;
    intnegtiveno=0;
    intpositivefractions=0;
    intnegativefractions=0;
%}

DIGIT [0-9]
%%

\+?{DIGIT}+    postiveno++;
-{DIGIT}+    negtiveno++;

\+?{DIGIT}*\.{DIGIT}+    positivefractions++;
-{DIGIT}*\.{DIGIT}+                negativefractions++;
. ;
%%

main()
{
    yylex();
    printf("\nNo. of positive numbers: %d",postiveno);
    printf("\nNo. of Negative numbers: %d",negtiveno);
    printf("\nNo. of Positive fractions: %d",positivefractions);
    printf("\nNo. of Negative fractions: %d\n",negativefractions);
}

Output:

nn@linuxmint ~ $ lexa.l
nn@linuxmint ~ $ gcclex.yy.c -ll
nn@linuxmint ~ $ ./a.out<a.txt

No. of positive numbers: 2
No. of Negative numbers: 3
No. of Positive fractions: 4
No. of Negative fractions: 5
nn@linuxmint ~ $

// Input file: a.txt
+12,-123,1.1,-1.1,12,-2,-3,2.1,3.2,5.1,-5.5,-6.1,-7.7,-8.8

b.Write a Lex program to printout all HTML tags in file

%{
#include<stdio.h>
%}
%%
(“<“|”<\\”)[a-z|A-Z|0-9]*”>” {printf(” “);}
%%
main()
{
yylex();
return 0;
}

Output:

<html>test file<\html>
test file

c.Write a Lex program which adds line numbers to the given file and display the sameonto the standard output.

%{
#include<stdio.h>
#include<string.h>
int ln=0;
%}
%%
“\n” {}
.* {ln++;fprintf(yyout,”\n%d:%s”,ln,yytext);}
%%
main()
{
yyin=fopen(“try1.txt”,”r”);
yyout=fopen(“try2.txt”,”w”);
yylex();
return 0;
}
Output:

try1.txt

hi
hello
test file

try2.txt

1:hi
2:hello
3:test file