Perl练习之——循环语句

#if elsif else 条件语句

$i = <STDIN> ;
chomp $i ;
if($i < 10){
?? ?print "Number is less than 10" ;
} elsif($i > 20){
?? ?print "Number is more than 20" ;
} else{
?? ?print "Number is between 10 and 20." ;
}

#循环语句
$counter = 0 ;
while($counter < 5){
?? ?print "counter is $counter,? " ;
?? ?print "$counter 小于5，进行循环n" ;
?? ?$counter++ ?
}


#for 循环
$i = 5 ;
for(;$i >2;){
?? ?print "i is $in" ;
?? ?$i--
}
$i = 5 ;
for(;$i>2;$i--){ ?? ?print "is now is $i n" ; }