# tst_median.pl - a program to test a function that
#                 computes the median of a given array

# median - a function
# Parameters:
#     The number of elements in the second parameter
#     An array of numbers
# Return value:
#     The median of the array, where median is the 
#      middle element of the sorted array, if the
#      length is odd; if the length is even, the median
#      is the average of the two middle elements of the
#      sorted array

sub median {
    my $len = $_[0];
    my @list = @_;

# Discard the first element of the array

    shift(@list);

# Sort the parameter array

    @list = sort @list;

# Compute the median

    if ($len % 2 == 1) {  # length is odd
        return $list[$len / 2];
    } else {  # length is even
        return ($list[$len / 2] + $list[$len / 2 - 1]) / 2;
    }
     
}  # End of function median

# Begin main program
# Create two test arrays

@list1 = (1, 3, 5, 2, 4, 6, 8, 0, 9);
@list2 = (4, 7, 1, 2, 8, 5, 9, 0);

# Call median on both arrays and display the results

$med = median(9, @list1);
print "The median of the first array is: $med \n";
$med = median(8, @list2);
print "The median of the second array is: $med \n";