use List::Util qw/ min max sum /;
$a = -55;$b = -54;
$c = -55;$d = -54;
for (1..110)
{
$file = "x_$a\_to_$b\_y$c\_to_$d";#file name

open(INFILE,"<","$file") or die("Couldn't open file for reading!\n");

while(<INFILE>){
    push @column8,(split(/\s+/,$_))[7];
}
$ZMAX = max @column8;print "maxZ $ZMAX\n";
$ZMIN = min @column8;print "minZ $ZMIN\n";
$thick = $ZMAX - $ZMIN;

print "$thick\n";
$c++;
$d++;
}