How can I get mouse position with irrlicht?

I wrote a example for take the mouse inputs on the button. I mean when user click the screen, I want see what mouse position x and mouse position Y. But X and Y always have junk value. This is my code:

#include <irrlicht.h>
#include <iostream>
using namespace std;
using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;


// Declare a structure to hold some context for the event receiver so that it
// has it available inside its OnEvent() method.
struct SAppContext
{
    IrrlichtDevice *device;
};

// Define some values that we'll use to identify individual GUI controls.
enum
{
    GUI_ID_BUTTON = 101,
};


class MyEventReceiver : public IEventReceiver
{
    public:
        MyEventReceiver(SAppContext & context) : Context(context) { }

        virtual bool OnEvent(const SEvent& event)
        {
            if (event.EventType == EET_GUI_EVENT)
            {
                s32 id = event.GUIEvent.Caller->getID();

                switch(event.GUIEvent.EventType)
                {
                    case EGET_BUTTON_CLICKED:
                        switch(id)
                        {
                            case GUI_ID_BUTTON:
                                cout << "X: "<< event.MouseInput.X << endl;
                                cout << "Y: "<< event.MouseInput.Y << endl << endl;
                                return true;

                            default:
                                return false;
                        }
                        break;

                    default:
                        break;
                }
            }
            return false;
        }

    private:
        SAppContext & Context;
};


int main(int argc, char** argv)
{


    // create device and exit if creation failed

    IrrlichtDevice * device = createDevice( video::EDT_SOFTWARE, core::dimension2d<u32>(1280, 720));

    if (device == 0)
        return 1; // could not create selected driver.

    device->setWindowCaption(L"Irrlicht Engine - User Interface Demo");
    device->setResizable(true);

    video::IVideoDriver* driver = device->getVideoDriver();
    IGUIEnvironment* env = device->getGUIEnvironment();

    // add button
    env->addButton(rect<s32>(0,0,640,360), 0, GUI_ID_BUTTON,
            L"Button", L"Button");

    // Store the appropriate data in a context structure.
    SAppContext context;
    context.device = device;

    // Then create the event receiver, giving it that context structure.
    MyEventReceiver receiver(context);

    // And tell the device to use our custom event receiver.
    device->setEventReceiver(&receiver);

    /*
    That's all, we only have to draw everything.
    */

    while(device->run() && driver)
    if (device->isWindowActive())
    {
        driver->beginScene(true, true, SColor(0,200,200,200));

        env->drawAll();

        driver->endScene();
    }

    device->drop();

    return 0;
}

And result image:

https://i.sstatic.net/dQEMs.png

How can I solve this problem? Is there another way for take the mouse inputs positions?

Irrlicht documentation has tutorial on how to use mouse and joystick for input. Read here.

You need to handle event of EMIE_MOUSE_MOVED and store mouse input current position somewhere.

if (event.EventType == irr::EET_MOUSE_INPUT_EVENT)
{
   switch(event.MouseInput.Event)
   {
       ...
       case EMIE_MOUSE_MOVED:
           MouseState.Position.X = event.MouseInput.X;
           MouseState.Position.Y = event.MouseInput.Y;
           break;
       ...
   }
}