TC392 Week 3 Programs
Note: Programs run on penguin can start the first line with the
following (shorter) perl path: #!/usr/bin/perl
w3.1.pl The "if" and "elsif" statements
<![CDATA[
#!/usr/bin/perl
#w3.1.pl statement blocks; if statement
print ("How many hotdogs would you like? ");
chomp($no= <STDIN>);
if ($no <= 0){
print ("So you are the vegetarian.\n");
}
elsif ($no <= 2){
print ("We can handle $no. \n");
}
elsif ($no >=3){
print ("We can put more on. ");
print ("By the way, you won't mind\nif we keep the ambulance handy.\n");
}
__END__
]]>
w3.2.pl A simple while statement.
<![CDATA[
#!/usr/bin/perl
#w3.2.pl while statement
@people = (Jim, Floyd, Fred, Jane, Marta, Jill, Sam, Joe, Alice, Andrea);
while (@people) {
$person = pop(@people);
print("$person\n");
}
__END__
]]>
w3.3.pl A more complex while statement
<![CDATA[
#!/usr/bin/perl
#w3.3.pl while statement (with last).
@people = (Jim, Floyd, Fred, Jane, Marta, Jill, Sam, Joe, Alice, Andrea);
print("Please enter your name: ");
chomp($name = <STDIN>);
while (@people) {
$try = pop(@people);
if ($try eq $name){
print("Yes, you can use our computer.\n");
$success = 1;
last;
} #End if statement
} #End while
if (!$success){ #The ! negates as in !=
print("Sorry $name, you are not on my list.\n");
}
__END__
]]>
w3.4.pl a complete for statement
<![CDATA[
#!/usr/bin/perl
#w3.4.pl the for statement
@people = (Jim, Floyd, Fred, Jane, Marta, Jill, Sam, Joe, Alice, Andrea);
print("Please enter your name: ");
chomp($name = <STDIN>);
for ($a=0;$a <= $#people; $a++) { # $#people counts @people
# print ("Last person is at sub $#people\n");
# print ("DEBUG: $people[$a]\n"); #DEBUG
if ($people[$a] eq $name){
print("Yes, you can use our computer.\n");
$success = 1;
last;
} #End if block
} #End for block
if (!$success){
print("Sorry $name, you are not on my list.\n");
}
__END__
]]>
w3.5.pl Things can be easier with foreach
<![CDATA[
#!/usr/bin/perl
#w3.5.pl foreach()
@people = (Jim, Floyd, Fred, Jane, Marta, Jill, Sam, Joe, Alice, Andrea);
print("Please enter your name: ");
chomp($name = <STDIN>);
foreach (@people){
# print ("Check $_\n"); #DEBUG
if ($_ eq $name){
print("Yes, $_, you can use our computer.\n");
$success = 1;
last;
} #End if block
} #End for block
if (!$success){
print("Sorry, $name, you are not on my list.\n");
}
__END__
]]>
w3.6.cgi: Import a text file. Add <p> to all blank lines. Put an
HTML header on the file so that a browser can display it.
<![CDATA[
#!/usr/bin/perl
#w3.6.cgi
open (FH, "sample.txt");
while (<FH>){ #puts each line from FH in $_
@lines = (@lines, $_);
}
##Print the HTML header
print("Content-type: text/html\n\n");
print <<EOT
<html>
<head> <title> Tc392 w3.6.cgi </title> </head>
<body bgcolor="#ffffe9">
<h1> Instant HTML Paragraphs</h1>
EOT
;
foreach (@lines){
if ($_ eq "\n"){
$_ = "<p>\n";
}
print ("$_");
}
print("</body></html>\n");
__END__
]]>
w3.8.cgi if and elsif statements; using split with assignment
<![CDATA[
#!/usr/bin/perl
# w3.8.cgi A different background color for each day of the week.
#PART 1: Print the header.
print ("Content-type: text/html\n\n");
print <<EOT
<html>
<head> <title>Penguin</title> </head>
EOT
;
#PART 2: Determine background color by Day of week
chomp($date= `date`);
# Date returns (for instance): Wed Feb 5 15:40:44 EST 1997
($today, $month, $dayno, $time, $zone, $year)= split(/ +/, $date);
if ($today eq "Sun") {print ("<body bgcolor=\"#ff0000\" text=\"#ffffff\">\n");}
elsif ($today eq "Mon") {print("<body bgcolor=\"#ff3333\" text=\"#ffffff\">\n");}
elsif ($today eq "Tue") {print ("<body bgcolor=\"#ff7777\" text=\"#ffffff\">\n");}
elsif ($today eq "Wed") {print ("<body bgcolor=\"#eeff22\" text=\"#000000\">\n");}
elsif ($today eq "Thu") {print ("<body bgcolor=\"#ffCCCC\" text=\"#000000\">\n");}
elsif ($today eq "Fri") {print ("<body bgcolor=\"#ffDDDD\" text=\"#000000\">\n");}
else {print ("<body bgcolor=\"#ffffff\" text=\"#000000\">\n");}
#Part 3: Print the rest of the page
print <<EOT
<center><h1> A Horse of a Differnet Color. </h1></center>
Note: This page uses a different background color for each day of the week.<p>
EOT
;
print ("Today is <b>$today $month $dayno, $year</b> <p>\n");
print("</body></html>\n");
__END__
]]>
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