Issues to display Text from sfml - c++

Question

I would like to display text in my Windows thanks to sfml. But I don't arrived to do it, the texte just don't appear in the windows, that's really strange because I can display lines without difficulties !
Can you check my code and tell me what I need to change please ? :)
My main.cpp
int main()
{
bool sortir = false;
// Création de la pile de double
Pile<double> pile_double;
// Création de la pile de string
Pile<string> pile_string;
// Création du map
map<string, function<void()>> _map;
int largeur_fenetre = 300;
int hauteur_fenetre = 400;
// Création de la fenetre
sf::RenderWindow window(sf::VideoMode(largeur_fenetre, hauteur_fenetre), "Interpreteur NPI");
//copie largeur / longueur
push(pile_double, (double) largeur_fenetre);
push(pile_double, (double) hauteur_fenetre);
// on fait tourner le programme tant que la fenêtre n'a pas été fermée
while (window.isOpen())
{
// on traite tous les évènements de la fenêtre qui ont été générés depuis la dernière itération de la boucle
sf::Event event;
while (window.pollEvent(event))
{
cout << "passage 1er while" << endl;
// fermeture de la fenêtre lorsque l'utilisateur le souhaite
if (event.type == sf::Event::Closed)
window.close();
}
// effacement de la fenêtre en noir
window.clear(sf::Color::Black);
window.display();
cout << "coucou" << endl;
while (sortir == false)
{
cout << "Entrez la commande souhaité >";
string carac;
cin >> carac;
// Recherche du string dans le map
for (map<string, function<void()>>::iterator it = _map.begin(); it != _map.end(); ++it) // Debut recherche de la relation
{
// S'il est trouvé on demarre sa fonction associé
if (carac == it->first)
{
(it->second)();
pile_double.display();
pile_string.display();
window.display();
}
} // Fin de la recherche de la relation string -> fonction | Fin du For
if (carac == "exit")
{
sortir = true;
}
}
}
return 0;
}
fonction.cpp
void drawstr(Pile<double>& nomDeLaPile, sf::RenderWindow& window, Pile<string>& nomDeLaPile2)
{
sf::Text text;
sf::Font font;
text.setFont(font);
text.setString("Hello world");
text.setCharacterSize(24);
text.setColor(sf::Color::Red);
text.setStyle(sf::Text::Bold | sf::Text::Underlined);
window.draw(text);
}
My apologies for very bad English, I hope you understand anyways!

Answer 1

You do:
sf::Font font;
text.setFont(font);
But you don't load any font, you "set" an empty font...
Try something like that before:
if (!font.loadFromFile("arial.ttf"))
{
// error
}
But you shouldn't do that in the drawing function.
Font has to be loaded once when starting the application.

Answer 2

From the SFML tutorial:
Note that SFML won't load your system fonts automatically, i.e.
font.loadFromFile("Courier New") won't work. First because SFML
requires file names, not font names, and secondly because SFML doesn't
have a magic access to your system's font folder. So, if you want to
load a font, you need to have the font file with your application,
like other resources (images, sounds, ...).
SFML does not provide a default font, or an font for that matter.
When you created a Font object using:
sf::Font font;
it is an empty font. What you need to do is download a font from a website, such as http://www.dafont.com/ or find where the font files are on your computer.
Then you should load the font (from the same SFML tutorial):
sf::Font font;
if (!font.loadFromFile("arial.ttf"))
{
// error...
}