printing specific hash values perl -

i trying print hash values numbers have corresponding letters, new @ this, don't know how conditional statements run through each value put in on single line of user input. trying make cryptogram.

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#!/usr/bin/perl print "enter numbers corresponding letters\n";  chomp( $num = <>);  while ($num >= 0 && $num <= 27 || $num == 'c'){  %num_to_letter; $num_to_letter{"4"} = "a"; $num_to_letter{"9"} = "b"; $num_to_letter{"17"} = "c"; $num_to_letter{"5"} = "d"; $num_to_letter{"13"} = "e"; $num_to_letter{"7"} = "f"; $num_to_letter{"21"} = "g"; $num_to_letter{"6"} = "h"; $num_to_letter{"23"} = "i"; $num_to_letter{"15"} = "j"; $num_to_letter{"1"} = "k"; $num_to_letter{"20"} = "l"; $num_to_letter{"26"} = "m"; $num_to_letter{"19"} = "n"; $num_to_letter{"12"} = "o"; $num_to_letter{"2"} = "p"; $num_to_letter{"27"} = "q"; $num_to_letter{"11"} = "r"; $num_to_letter{"25"} = "s"; $num_to_letter{"3"} = "t"; $num_to_letter{"22"} = "u"; $num_to_letter{"14"} = "v"; $num_to_letter{"18"} = "w"; $num_to_letter{"8"} = "x"; $num_to_letter{"24"} = "y"; $num_to_letter{"16"} = "z"; $num_to_letter{"10"} = " ";  if ($num == 4){     print "$num $num_to_letter{$num}";     print $num_to_letter{"4"} = "a";  } elsif ($num == 9){     print "$num $num_to_letter{$num}";     print $num_to_letter{"9"} = "b"; } elsif ($num == 17 ){     print $num $num_to_letter{$num};     print $num_to_letter{"17"} = "c"; } elsif ($num == 5){     print $num $num_to_letter{$num};     print $num_to_letter{"5"} = "d"; } elsif ($num == 13 ){     print $num $num_to_letter{$num};     print $num_to_letter{"13"} = "e"; } elsif ($num == 7 ){     print $num $num_to_letter{$num};     print $num_to_letter{"7"} = "f";  } elsif ($num == 21){     print $num $num_to_letter{$num};     print $num_to_letter{"21"} = "g";    } elsif ($num == 6){     print $num $num_to_letter{$num};     print $num_to_letter{"6"} = "h";  } elsif ($num == 23){     print $num $num_to_letter{$num};     print $num_to_letter{"23"} = "i";  } elsif ($num == 15){     print $num $num_to_letter{$num};     print $num_to_letter{"15"} = "j";   } elsif ($num == 1){     print $num $num_to_letter{$num};     print $num_to_letter{"1"} = "k";     } elsif ($num == 20){     print $num $num_to_letter{$num};     print $num_to_letter{"20"} = "l"; } elsif ($num == 26){     print $num $num_to_letter{$num};     print $numto_letter{"26"} = "m";  } elsif ($num == 19){     print $num $num_to_letter{$num};     print $num_to_letter{"19"} = "n";     } elsif ($num == 12 ){     print $num $num_to_letter{$num};     print $num_to_letter{"12"} = "o";  } elsif ($num == 2){     print $num $num_to_letter{$num};     print $num_to_letter{"2"} = "p";     } elsif ($num == 27){     print $num $num_to_letter{$num};     print $num_to_letter{"27"} = "q";  } elsif ($num == 11){     print $num $num_to_letter{$num};     print $num_to_letter{"11"} = "r"; }  elsif ($num == 25){     print $num $num_to_letter{$num};     print $num_to_letter{"25"} = "s"; } elsif ($num ==3){     print "$num $num_to_letter{$num}";     $num_to_letter{"3"} = "t"; } elsif ($num == 22){     print $num $num_to_letter{$num};     $num_to_letter{"22"} = "u"; } elsif ($num == 14){     print $num $num_to_letter{$num};     $num_to_letter{"14"} = "v"; } elsif ($num == 18){     print $num $num_to_letter{$num};     $num_to_letter{"18"} = "w"; } elsif ($num == 8){     print $num $num_to_letter{$num};     $num_to_letter{"8"} = "x"; } elsif ($num == 24){     print $num $num_to_letter{$num};     $num_to_letter{"24"} = "y"; } elsif ($num == 16){     print $num $num_to_letter{$num};     $num_to_letter{"16"} = "z"; } elsif ($num == 10){     print $num $num_to_letter{$num};     $num_to_letter{"10"} = " "; } else{     print "you didn't enter jersey number have stats on.\n";} chomp($num = <>); } 

you have improve coding skill.

i suppose want perl script (i.e. crypt.pl) when called, this

$ perl crypt.pl 1 4 6 12 3 6 7 .. 

it returns

k h o t h f .. 

an example following one:

#!/usr/bin/perl -w # start use warnings; # scripts use strict; # these 3 lines  %num_to_letter = (   4 => "a",   9 => "b",   17 => "c",   5 => "d",   13 => "e",   7 => "f",   21 => "g",   6 => "h",   23 => "i",   15 => "j",   1 => "k",   20 => "l",   26 => "m",   19 => "n",   12 => "o",   2 => "p",   27 => "q",   11 => "r",   25 => "s",   3 => "t",   22 => "u",   14 => "v",   18 => "w",   8 => "x",   24 => "y",   16 => "z",   10 => " " ); # better way of # declaring , defining hash content  foreach $num (@argv) {   print $num_to_letter{$num} . " "; } # here how each value 

maybe add input validation.