Control structures

 1. foreach
To go through each line of an array or other list-like structure 
(such as lines in a file) Perl uses the foreach structure. This has the form

@books = ("book1","book2","book3");

foreach $thing (@books )		# Visit each item in turn
				# and call it $thing
{
	print "$thing\n";	# Print the item
	print "--------------- \n";	# That was nice
}


2. The loop for:

for ($i = 0; $i < 10; ++$i)	# Start with $i = 1
				# Do it while $i < 10
				# Increment $i before repeating
{
	print "$i\n";
}


3. While
---------
print "Password? ";		# Ask for input
$a = ;			# Get input
chop $a;			# Remove the newline at end
while ($a ne "fred")		# While input is wrong...
{
    print "sorry. Again? ";	# Ask again
    $a = ;		# Get input again
    chop $a;			# Chop off newline again
}


4. chop() function
------------------
removes and returs the last character from a string.
chomp(0 removes a new line

Example:
--------
    my @array = ("bob\n", "jill", "fred\n");

  print "Before chomp:\n";
  print "@array\n";

  chomp(@array);

  print "After chomp:\n";
  print "@array\n";

  outputs
  ---------
  bob
 jill fred

After chomp:
bob jill fred



4. Do while:
-----------
do
{
	"Password? ";		# Ask for input
	$a = ;		# Get input
	chop $a;		# Chop off newline
}
while ($a ne "fred")		# Redo while wrong input