I'm looking for a maybe 1980s film about American recruits. The soldiers were trained in America, and once they arrived in Vietnam, the war ended. Some details: the chief actor always keep a diary (not very sure about this); he fell in love with a Catholic student, and he had several dances with her; he gave his virginity to a hooker who sold cosmetics; the last scene is soldier chatting on the train to Vietnam with the background voice recalling.
