Calculator in PHP GTK2

Free Simple Calculator in php gtk2 with source code. This calculator perform basic arithmetic operations i.e Addition, Subtraction, Multiplication, Division. Hope you like it. Thanks! For reading my Blog.

<?php
/* 
PHP GTK tutorials
website: http://phpgtktutorials.blogspot.in/
*/

if (!class_exists('gtk')) {
    die("Please load the php-gtk2 module in your php.ini\r\n");
}


$wnd = new GtkWindow();
$action = NULL;
$firstValue = NULL;
$result =NULL;

function pressClear(GtkWindow $wnd, GtkEntry $txtEntry, $txtButton)
{
    //clear $txtEntry
    $txtEntry->set_text($txtButton);
    
}

function pressBack(GtkWindow $wnd, GtkEntry $txtEntry)
{
    //backspace
    $txtEntryValue = $txtEntry->get_text();
    $newTxtEntryValue = substr("$txtEntryValue", 0, -1);
    $txtEntry->set_text($newTxtEntryValue);
}


function pressAction(GtkWindow $wnd, GtkEntry $txtEntry, $currentAction, $label, $action)
{

$firstValue = $txtEntry->get_text();
$txtEntry->set_text(NULL);

$label->set_text($firstValue);
$action->set_text($currentAction);


}


function pressEqualto(GtkWindow $wnd, GtkEntry $txtEntry, $action, $label)
{
    $secondValue = $txtEntry->get_text();
    $firstValue = $label->get_text();
    $currentaction = $action->get_text();

    if($currentaction=="+")
    {
        $result = $firstValue+$secondValue;
    }
    elseif ($currentaction=="*") {
        
        $result = $firstValue*$secondValue;
    }
    elseif ($currentaction=="/") {
        
        $result = $firstValue/$secondValue;
    }
    elseif ($currentaction=="-") {
        
        $result = $firstValue-$secondValue;
    }

    $txtEntry->set_text($result);


}



function pressButton(GtkWindow $wnd, GtkEntry $txtEntry, $txtButton)
{
    //get the values from the widgets into variables
    $txtEntryValue = $txtEntry->get_text();
    

    if(empty($txtEntryValue))
    {

        $txtEntry->set_text($txtButton);
        
    }else{

        $txtEntry->set_text($txtEntryValue.$txtButton);

    }    



}



        $wnd->set_title('Calculator');         
        $wnd->connect_simple('destroy', array('gtk', 'main_quit')); 

        $vbox = new GtkVBox(false, 2);

        $mb = new GtkMenubar();
        $filemenu = new GtkMenu();
        $filemi = new GtkMenuItem("File");
        $filemi->set_submenu($filemenu);
        $mb->append($filemi);

        $vbox->pack_start($mb, false, false, 0);

        $table = new GtkTable(5, 4, true);

        // Set up all the widgets we need
        $btnClose = new GtkButton("_Close");

        $btnOne = new GtkButton("1");
        $btnTwo = new GtkButton("2");
        $btnThree = new GtkButton("3");
        $btnFour = new GtkButton("4");
        $btnFive = new GtkButton("5");
        $btnSix = new GtkButton("6");
        $btnSeven = new GtkButton("7");
        $btnEight = new GtkButton("8");
        $btnNine = new GtkButton("9");
        $btnZero = new GtkButton("0");

        $btnClear = new GtkButton("Clear");
        $btnBack = new GtkButton("Clear Entry");

        $btnAddition = new GtkButton("+");
        $btnDivide = new GtkButton("/");
        $btnMinus = new GtkButton("-");
        $btnProduct = new GtkButton("*");
        $btnEqualto = new GtkButton("=");

        $labelHidden = new GtkLabel(); // store firstvalue
        $labelAction = new GtkLabel(); // store operations

        $table->attach($btnClear, 0, 1, 0, 1);
        $table->attach($btnBack, 1, 2, 0, 1);
        @$wnd->set_title($labelHidden);
        @$wnd->set_title($labelAction);

        $table->attach($btnClose, 3, 4, 0, 1);

        $table->attach($btnSeven, 0, 1, 1, 2);
        $table->attach($btnEight, 1, 2, 1, 2);
        $table->attach($btnNine, 2, 3, 1, 2);
        $table->attach($btnDivide, 3, 4, 1, 2);

        $table->attach($btnFour, 0, 1, 2, 3);
        $table->attach($btnFive, 1, 2, 2, 3);
        $table->attach($btnSix, 2, 3, 2, 3);
        $table->attach($btnProduct, 3, 4, 2, 3);

        $table->attach($btnOne, 0, 1, 3, 4);
        $table->attach($btnTwo, 1, 2, 3, 4);
        $table->attach($btnThree, 2, 3, 3, 4);
        $table->attach($btnMinus, 3, 4, 3, 4);

        $table->attach($btnZero, 0, 1, 4, 5);
        $table->attach(new GtkButton("."), 1, 2, 4, 5);
        $table->attach($btnEqualto, 2, 3, 4, 5);
        $table->attach($btnAddition, 3, 4, 4, 5);

        $txtEntry = new GtkEntry();
        $vbox->pack_start($txtEntry, false, false, 0);
        $vbox->pack_end($table, true, true, 0);

        $wnd->add($vbox);        


        // Destroy the window when the user clicks Close button
        $btnClose->connect_simple('clicked', array($wnd, 'destroy'));

        // Clear entry label  when the user clicks Clear button
        $btnClear->connect_simple('clicked', 'pressClear', $wnd, $txtEntry, NULL);

        // BackSpace label  when the user clicks Back button
        $btnBack->connect_simple('clicked', 'pressBack', $wnd, $txtEntry);

        // Call the pressEqualto function 
        $btnEqualto->connect_simple('clicked', 'pressEqualto', $wnd, $txtEntry, $labelAction, $labelHidden);

        // Call the pressAction function when the user clicks on numeric button
        $btnAddition->connect_simple('clicked', 'pressAction', $wnd, $txtEntry, "+", $labelHidden, $labelAction);
        $btnDivide->connect_simple('clicked', 'pressAction', $wnd, $txtEntry, "/", $labelHidden, $labelAction);
        $btnMinus->connect_simple('clicked', 'pressAction', $wnd, $txtEntry, "-", $labelHidden, $labelAction);
        $btnProduct->connect_simple('clicked', 'pressAction', $wnd, $txtEntry, "*", $labelHidden, $labelAction);
 
        // Call the pressButton function when the user clicks on numeric button
        $btnOne->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "1");
        $btnTwo->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "2");
        $btnThree->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "3");
        $btnFour->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "4");
        $btnFive->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "5");
        $btnSix->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "6");
        $btnSeven->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "7");
        $btnEight->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "8");
        $btnNine->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "9");
        $btnZero->connect_simple('clicked', 'pressButton', $wnd, $txtEntry, "0");


        $wnd->set_default_size(300, 250); 
        $wnd->set_position(GTK::WIN_POS_CENTER);
                
 

//Show all widgets
$wnd->show_all();
//Start the main loop
Gtk::main();

?>