Prof. Alfred J Bird, Ph.D., NBCT
[email protected]
http://it441-f11-campbell.wikispaces.umb.edu/
Door Code for IT441 Students – 142864*
Office – Wheatly 2nd floor 096-03
Office Hours – MW 3:00PM to 4:00PM
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exit (0);
die $string;
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A very helpful construct is the
increment/decrement statement
$i++ is equivalent to $i = $i+1
$j = $i++
 $j = ++$i
 $j = $i -  $j = - - $i
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$x > $y
$x < $y
$x >= $y
$x < =$y
$x == $y
$x != $y
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$x gt $y
$x lt $y
$x ge $y
$x le $y
$x eq $y
$x ne $y
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$x and &y
$x && $y
$x or $y
$x || $y
Not $x
!$x
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What is a control statement?
Types of control statements:
if
 while
 for
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if
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if else
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if ( condition ) { action }
if (condition ) { action }
else {another action }
if elsif else
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if ( condition ) { action }
elsif (another condition ) { another action }
…
else { a further action }
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while loops
while ( condition ) { action }
$i=1;
 while ($i<=5) {
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print $i, “\n”;
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$i++;
 }
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$_ is the default variable for many functions
while ( $line = <STDIN>) {
chomp ($line);
 …
 }
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while (<STDIN>) {
chomp;
 …
 }
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for loop
for ( init_exp ; test_exp; step_exp) { action }
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for ($i=1; $i<5; $i++) {print $i, “\n”;}
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foreach my $number (1..10) {
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print “The number is: $number \n”;
}
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Read Chapter 3 “Control Flow Constructs”
pp 53-79
Exercises 1, 2 & 3 on page 79