#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my $path = shift || '.';

my @files = `find $path -name '*.c' -o -name '*.txt'`;

chomp @files;
print Dumper \@files;

__DATA__

$ perl file.pl
$VAR1 = [
          './test.pl~',
          './sample.c',
          './test.txt~',
          './testDir/anotherSample.c',
          './test.pl',
          './test.txt'
        ];