cardiac-output.pl

#!/usr/bin/perl
eval 'exec /usr/bin/perl -S $0 ${1+"$@"}'
    if $running_under_some_shell;
			# this emulates #! processing on NIH machines.
			# (remove #! line above if indigestible)

eval '$'.$1.'$2;' while $ARGV[0] =~ /^([A-Za-z_0-9]+=)(.*)/ && shift;
			# process any FOO=bar switches

#/usr/bin/awk -f

$, = ' ';		# set output field separator
$\ = "\n";		# set output record separator

print 'Cardiac Output Calculator';
print '=========================';
printf (('Please, enter the stroke volume [mL/min]:  '));
$SV = &readline();
while ($SV <= 0) {
    print 'out of range, please, retype the stroke volume: ';
    $SV = &readline();
    if ($SV > 0) {
	last;
    }
}
printf (('Please, enter the Heart Rate [bpm]:  '));
$HR = &readline();
while ($HR <= 0) {
    print 'out of range, please, retype the stroke volume: ';
    $HR = &readline();
    if ($HR > 0) {
	last;
    }
}
$CO = $SV * $HR;
$Q = $CO / 1000;
{
print 'The cardiac output formula is CO = SV * HR';
print 'The cardiac output is ' . $Q . ' L/min';
print 'The cardiac output is ' . $CO . ' mL/min';
last;
}
sub readline {
    if ($getline_ok = (($_ = <>) ne '')) {
	;
    }
    $_;
}
while (1) {
print "Do you want to save the output to file (co.txt) [yes/no]? ";
my $ans = lc(<STDIN>);
chomp($ans);
if ($ans eq 'yes')  {	   
    my $output = 'co.txt';
open(FH,'>', $output) or die $!;
print FH 
my $str = <<END;
The cardiac output formula is CO = SV * HR
The cardiac output is  $Q  L/min
The cardiac output is  $CO  mL/min
END
# print FH $str;
close(FH);
    print "written to co.txt\n";
    last;
}	
elsif ($ans eq 'no') {
    print "Not saved\n";
    last;
	}
else {
print "out of range, please answer [yes or no] ";
 }
}