#!/usr/bin/perl -w
$pi3.14159;
print"what is the $radius \n";
chomp($radius<STDIN>);
$circuit=2*$pi*$radius;
print"this is the circumference of a circle r $radius is\n";
##</code><code>##

#!/usr/bin/perl -w
@names=qw/shanghai beijing nanjing hubei/;
print "Enter some numbers from 1 to 4, one per line,then press Ctrl-Z.\n";
chomp(@number=<STDIN>);
foreach(@names){
  print "$names[$_-1]\n";
}