Hi,
i have one hash tables that contains data stings and information. I have one c file , i need to search the file and if i found stings in the c file i need to add information at the top of the c file. I am very beginer to perl, i have written code like this
code:
#!/usr/bin/perl
use warnings;
use strict;
open (my $code , “<”, ‘c.c’);
my %strings = (‘string1’=>"information
",
‘string2’=>"information2
",
‘string3’=>"information3
",
);
my $test_string=“(” .join(“|”, keys %strings).“)” ;
while(<$code>){
if (/$test_string/){
chomp;
$.=$strings{$1};
}
print $
}
this code adding the information before the string, i need to add at the top of the c file. what should i do in this case.
Sadly, there’s no way to insert information at the beginning of a file without having to rewrite the whole thing, so you’ll need to read in the entire file (rather than just one line at a time), determine which string(s) appear in the contents, write the corresponding information item(s) to a new file, and (finally!) write the original contents to the new file:
#!/usr/bin/env perl
use strict;
use warnings;
use File::Slurp;
my %strings = (
'string1' => "information \
",
'string2' => "information2 \
",
'string3' => "information3 \
",
);
my $test_string = "(" . join("|", keys %strings) . ")";
# First make a list of all matched strings (including the number of times
# each was found, although I assume that's not actually relevant)
my $code = read_file('c.c');
my %found;
while ($code =~ /$test_string/g) {
$found{$1}++;
}
# If %found is empty, we didn't find anything to insert, so no need to rewrite
# the file
exit unless %found;
# Write the prefix data to the new file followed by the original contents
open my $out, '>', 'c.c.new';
for my $string (sort keys %found) {
print $out $strings{$string};
}
print $out $code;
# Replace the old file with the new one
rename 'c.c.new', 'c.c';