 3 

 3   5  6   6         



   ""   ( Condition )   Perl  5  

if
if . Else
while



 if

if     if    if   if 

if (  ) {



}

 if    {.}   if1.pl   if

 if1.pl

$num = 20;

if ( $num == 20 ) {

print "number is 20";

}



number is 20

  $num  20  if  $num  20       if   ( TRUE )  if1.pl  $num  20  

   if  

if ( num == 20 ) printf("number is 20");

 Perl  

 String   if2.pl 

 if2.pl

$name = "yoyo";

if ( $name eq "yoyo" ) {

print "hello , yoyo";

}



hello , yoyo

    ==  eq  equal ( "")  ==  eq    3.1   Perl


	Numbers	Strings
$x  $y	$x == $y	$x eq $y
$x  $y	$x != $y	$x ne $y
$x  $y	$x > $y	$x gt $y
$x  $y	$x >= $y	$x ge $y
$x  $y	$x < $y	$x lt $y
$x  $y	$x <= $y	$x le $y

 chop1.pl   if2.pl   "yoyo"  hello , yoyo

 chop1.pl

print "Enter your name : ";
$name = <STDIN>;
chop($name);
if ($name eq "yoyo"){

print "\nhello , $name";

}



Enter your name : yoyo
hello , yoyo

 chop1.pl   yoyo  chop()  if   ..    Enter   Enter  newline charactor    "yoyo"  Enter  $name  5  y , o , y , o  \n  newline charactor   $name  If    $name  1    chop() 

  \n 

 1 

 if   1   1   || ( OR )  && ( AND ) 

 OR  ""   if   ||
 AND  ""     if   &&

 if3.pl

 if3.pl

$a = 10;
if ( ($a==20) || ($a==10) ) {

print "that is true";

}

  $a  10  if  if  "$a  20  $a  10 "  $a  10  ( $a==10)   "that is true" 

  if4.pl 

 if4.pl

$a=50;
if ( ($a>=50) && ($a==50)){

print "that is true";

}

  $a  50   if  "$a  50  $a  50 "  $a  50   2   that is true   $a  60  .

 $a  60      if  "that is true"..

if  Else

 else  if   if    

 ifelse1.pl

$name = "yoyo";
if ( $name eq "yoyo" ) {

print "hello , yoyo";

}else{

print "good bye";

}

 ifelse2.pl

$name = "yooooo";

if ( $name eq "yoyo" ) {

print "hello , yoyo";

}else{

print "good bye";

}

 while

 C    while  if  while   while1.pl 

 while1.pl

$count = 0;

while ($count != 10){

print "$count\n";

$count++;

}

  $count   $count  10   10  1  

 Perl

 Perl   while     ...

 

for
foreach
until

 for

 for   

for( = ;  ;  ) {



}

 for     $  

 for1.pl

$name= "kwangd DevMan";

for ($count=0;$count<=10;$count++){

print "$name\n";

}

 for1.pl  kwangd DevMan  10 

 for   {}  .....

 foreach

 foreach  Array  foreach     

 foreach1.pl

@data = ("hello1","hello2","hello3");

foreach $a (@data){

print "$a\n";

}

 foreach1.pl 

hello1

hello2

hello3

  @data  hello1 , hello2  hello3   foreach 