SFML Demo - Not working

// Standard C++ headers
#include <iostream>
using namespace std;

// SFML headers
#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
using namespace sf;

int main()
{
    /* INITIALIZATION */
    Event evt;

    // Create and load textures and sprites
    Texture tex;
    if(!tex.LoadFromFile("data/sprites/UFO/single.png"))
        return EXIT_FAILURE;

    Sprite sprite(tex);

    // Create the render window
    RenderWindow win(VideoMode(800, 600), "ProjectX - development version");

    /* MAIN LOOP */
    while(win.IsOpen())
    {
        // Clear back buffer
        win.Clear();

        // Process events
        while(win.PollEvent(evt))
        {
            // Exit if the user presses ESC or clicks on window close button
            if(evt.Type == Event::Closed || (evt.Type == Event::KeyPressed and evt.Key.Code == Keyboard::Escape))
                win.Close();
        }

        win.Draw(sprite);

        // Display changes
        win.Display();
    }

    return 0;
}