I found out more about the movie.
Made right before Steve McQueen did Great Escape.
Two Naval officers were on leave and ran into civilian at the Lido casino who said that
odds could be computed if they knew the past series of positions of the roulette ball.
They recorded the positions and used a signal lamp to send them to their ship, officer on
ship entered them into computer and relayed via signal lamp back the predicted next
winning position. I think they always bet on the top 3 predicted positions.
They were staying in a suite at the hotel and ran into a cute young women who turned out
to be the admiral's daughter. The admiral was staying at the suite downstairs and
noticed the flashing signal lamp and thought there were spies around. Nobody could decode
the Morse code signals of the roulette positions.
Finally all were found out and confessed to the "gambling".
Mike