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PERL I/O question

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# 1  
Old 01-31-2009
CPU & Memory PERL I/O question
Playing with an until loop as follows:

my $input;

until ($input eq "quit") {
print "Please enter something:";
$input = <STDIN>;
chomp $input;
if ($input eq "dog") {
print "cat" ;
}
else {
print "Please re-enter";
}
}


Something simple like this...

I want to prompt the user to enter something. Whatever they enter, print something and ask again, unless they say "quit" and then quit.

Trying to get a handle on the until() loop and am either getting one of the following problems:
1. Infinite loop/print on "please enter something"
2. The program quits after I enter something
# 2  
Old 01-31-2009
"until" is not a loop, it is a condition. What you want is "while". "while" is a loop and you can use loop commands to control the loop:

next
redo
last

The old standard for what you are doing is:

Code:
while(1){
   ...
}

heres a working example I recently posted on another forum:

Code:
use strict;
use warnings;

my $thinkingof = int(rand 10)+1;
while (1) {
   print "Pick a number 1 to 10\n";
   my $guess = <STDIN>;
   chomp $guess;
   if ($guess > $thinkingof){
      print "You guessed too high\n";
      next;
   }
   elsif ($guess < $thinkingof){
      print "You guessed too low\n";
      next;
   }
   print "YOU GUESSED RIGHT!! It was $guess\n";
   last;
}

# 3  
Old 01-31-2009
Actually, you can do this:

Code:
use strict;
use warnings;

my $thinkingof = int(rand 10)+1;
until (0) {
   print "Pick a number 1 to 10\n";
   my $guess = <STDIN>;
   chomp $guess;
   if ($guess > $thinkingof){
      print "You guessed too high\n";
      next;
   }
   elsif ($guess < $thinkingof){
      print "You guessed too low\n";
      next;
   }
   print "YOU GUESSED RIGHT!! It was $guess\n";
   last;
}

# 4  
Old 02-01-2009
Great, thanks. I'll need to look into how and why this works. But it did.
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