use Tk; 
 
my $expression= ''; 
 
sub evalexpression 
 
	{ 
 
	my $result; 
	$result = eval($expression); 
 
	if ($@) 
 
		{ 
 
		$expression = $@; 
 
		} 
 
	else 
 
		{ 
 
		$expression = $result; 
 
		} 
 
	} 
 
sub all_clear 
 
	{ 
 
	$expression = ''; 
 
	} 
 
sub insert 
 
	{ 
 
	$expression .= $_[0]; 
 
	} 
 
sub calctest_ui  
 
	{ 
 
	my ($root) = @_; 
 
	# Widget Creation. 
 
	my ($expression) = $root->Entry (-textvariable => \$expression,); 
	my ($button7) = $root->Button (-text => '7',); 
	my ($button8) = $root->Button (-text => '8',); 
	my ($button9) = $root->Button (-text => '9',); 
	my ($buttonoff) = $root->Button (-text => 'off',); 
	my ($buttonAC) = $root->Button (-text => 'AC',); 
	my ($button4) = $root->Button (-text => '4',); 
	my ($button5) = $root->Button (-text => '5',); 
	my ($button6) = $root->Button (-text => '6',); 
	my ($buttontimes) = $root->Button (-text => '*',); 
	my ($buttondivide) = $root->Button (-text => '/',); 
	my ($button1) = $root->Button (-text => '1',); 
	my ($button2) = $root->Button (-text => '2',); 
	my ($button3) = $root->Button (-text => '3',); 
	my ($buttonplus) = $root->Button (-text => '+',); 
	my ($buttonminus) = $root->Button (-text => '-',); 
	my ($button0) = $root->Button (-text => '0',); 
	my ($buttonperiod) = $root->Button (-text => '.',); 
	my ($buttonleft) = $root->Button (-text => '(',); 
	my ($buttonright) = $root->Button (-text => ')',); 
	my ($buttonequals) = $root->Button (-text => '=',); 
 
	# Widget Commands. 
 
	$button7->configure(-command => sub { insert '7'; }); 
	$button8->configure(-command => sub { insert '8'; }); 
	$button9->configure(-command => sub { insert '9'; }); 
	$buttonoff->configure(-command => sub { exit(); }); 
	$buttonAC->configure(-command => \&all_clear); 
	$button4->configure(-command => sub { insert '4'; }); 
	$button5->configure(-command => sub { insert '5'; }); 
	$button6->configure(-command => sub { insert '6'; }); 
	$buttontimes->configure(-command => sub { insert '*'; }); 
	$buttondivide->configure(-command => sub { insert '/'; }); 
	$button1->configure(-command => sub { insert '1'; }); 
	$button2->configure(-command => sub { insert '2'; }); 
	$button3->configure(-command => sub { insert '3'; }); 
	$buttonplus->configure(-command => sub { insert '+'; }); 
	$buttonminus->configure(-command => sub { insert '-'; }); 
	$button0->configure(-command => sub { insert '0'; }); 
	$buttonperiod->configure(-command => sub { insert '.'; }); 
	$buttonleft->configure(-command => sub { insert '('; }); 
	$buttonright->configure(-command => sub { insert ')'; }); 
	$buttonequals->configure(-command => sub { insert '='; }); 
 
	# Geometry Management. 
 
	$expression->grid(-in => $root, -column => '1', -row => '1', -columnspan => '5'); 
	$button7->grid(-in => $root, -column => '1', -row => '2');  
	$button8->grid(-in => $root, -column => '2', -row => '2');    
	$button9->grid(-in => $root, -column => '3', -row => '2');   
	$buttonoff->grid(-in => $root, -column => '4', -row => '2');   
	$buttonAC->grid(-in => $root, -column => '5', -row => '2');   
	$button4->grid(-in => $root, -column => '1', -row => '3');   
	$button5->grid(-in => $root, -column => '2', -row => '3');   
	$button6->grid(-in => $root, -column => '3', -row => '3');   
	$buttontimes->grid(-in => $root, -column => '4', -row => '3');   
	$buttondivide->grid(-in => $root, -column => '5', -row => '3');   
	$button1->grid(-in => $root, -column => '1', -row => '4');   
	$button2->grid(-in => $root, -column => '2', -row => '4');   
	$button3->grid(-in => $root, -column => '3', -row => '4');   
	$buttonplus->grid(-in => $root, -column => '4', -row => '4');   
	$buttonminus->grid(-in => $root, -column => '5', -row => '4');   
	$button0->grid(-in => $root, -column => '1', -row => '5');   
	$buttonperiod->grid(-in => $root, -column => '2', -row => '5');   
	$buttonleft->grid(-in => $root, -column => '3', -row => '5');   
	$buttonright->grid(-in => $root, -column => '4', -row => '5');   
	$buttonequals->grid(-in => $root, -column => '5', -row => '5');  
 
	# Resize Behavior Managment. 
 
	$root->gridColumnconfigure(1, -weight => 0, -minsize => 2); 
	$root->gridColumnconfigure(2, -weight => 0, -minsize => 13); 
	$root->gridColumnconfigure(3, -weight => 0, -minsize => 13); 
	$root->gridColumnconfigure(4, -weight => 0, -minsize => 30); 
	$root->gridColumnconfigure(5, -weight => 0, -minsize => 30); 
	$root->gridRowconfigure(1, -weight => 0, -minsize => 30); 
	$root->gridRowconfigure(2, -weight => 0, -minsize => 17); 
	$root->gridRowconfigure(3, -weight => 0, -minsize => 8); 
	$root->gridRowconfigure(4, -weight => 0, -minsize => 7); 
	$root->gridRowconfigure(5, -weight => 0, -minsize => 2); 
 
	} 
 
$main = MainWindow->new(); 
$main->title("Calculator"); 
 
calctest_ui($main); 
 
MainLoop(); 
 
 
################################# 
 
$a = $ARGV[0]; 
$b = $ARGV[2]; 
$operation = $ARGV[1]; 
 
if ($operation eq "+") { 
        $result = $a + $b; 
} 
elsif ($operation eq "-") { 
        $result = $a - $b; 
} 
elsif ($operation eq "/") { 
        $result = $a / $b; 
} 
elsif ($operation eq "x") { 
        $result = $a * $b; 
}