How do u know if guys flirt with you?

like, what do they do to let u know they like u without actually telling u?How do u know if guys flirt with you?
They smile when they talk to you and laugh for no reason. Or if you don't go by them they have the guts to go talk to youHow do u know if guys flirt with you?
They look at you right in the eye and it feels like they are sucking you in. They casually touch you, or pick some ';lint' off you. They hint, they laugh extra hard, they tell you story of how tough they are. They offer you something.. anything lunch, carry your books, a ride.. etc.. they just want to be near you. have fun flirty!
they kinda smile and stare at you .Then when they get the courage to ask u out they walk up to.