Sorry, I tried mentioned solution, but it doesnt work, please can you check my code?
sf::Font myfont;
myfont.LoadFromFile("courier.ttf");
((sf::Texture&)myfont.GetTexture(12)).SetSmooth(false);
sf::Text Text(str,myfont,12);
Text.SetColor(sf::Color(0,0,0));
Text.SetPosition(150,3);
App.Draw(Text);