# Project = 00 
# Description = computes frequency of a character
# Program = computeFrequency.pl
# Input = sequence.txt 
# Output = STDOUT
# Usage = perl computeFrequency.pl
# Name = Your name
# UT EID = Your eid
# Comments (or README) = Describe some thing ...

$filename = "sequence.txt";

open (SEQUENCE, '<', $filename) 
  or die "Can't open the file: $filename\n";

while (<SEQUENCE>){
  $line = $_;
  chomp($line);
  $length = length($line);

  for ($i = 0; $i < $length; $i++){
    $char = substr($line, $i, 1);
    $charCount{$char}++;
  }
}

close(SEQUENCE);

foreach $char (keys %charCount){
  print "The character $char occurs $charCount{$char} times.\n";
}