for my $y ( @a ) {...}

##</code><code>##

foreach my $y ( @a ) {...}

##</code><code>##

foreach ( $x=0; $x < $#a; $x++ ) {my $y=$a[$x];...}

##</code><code>##

for ( $x=0; $x < $#a; $x++ ) {my $y=$a[$x];...}