The Honeymoon Machine

The Honeymoon Machine is a 1961 film directed by Richard Thorpe and starring Steve McQueen, Brigid Bazlen, Jim Hutton, Paula Prentiss, Jack Mullaney, and Dean Jagger, based on the 1959 Broadway play The Golden Fleecing by Lorenzo Semple Jr.. In the film, three men devise a plan to win at roulette with a United States Navy computer. The scheme works until an admiral ruins their plans.

At the hotel dedicated bachelor Howard meets and romances Julie Fitch Bazlen, the admirals daughter. Eldridge reunites with former girlfriend and heiress Pam Dunstan Prentiss, in Venice to marry another man. The betting system is very effective, and the three men accumulate hundreds of thousands of dollars in casino chips the money gives Eldridge the confidence to propose to Dunstan. However, Admiral Fitch sees and investigates their signals soon the Navy, the American and Soviet consulates, and Venice city authorities are on alert for a revolution.The gamblers get Signalman Burford Taylor Weston, who finds their signal lamp, drunk to detain him, but Taylor escapes and reports to the admiral. Julie Fitch tells her father that she and Howard have got to marry each other to save him from courtmartial. The Soviets accuse the Navy of using MACS to steal from the casino. To avoid an international incident Howard agrees to intentionally lose his last bet, but a riot breaks out between Soviets, Americans, and Italians in the casino over the chips. The movie ends with newlyweds Howard and Fitch celebrating their honeymoon in the hotel. ........

Source: Wikipedia