A Sitcom is a genre of comedy which have characters that live together in the same environment or house.
Usually sitcoms have characters who don’t have a lot of depth or change throughout the shows. The setting normally remains the same and the problems that occur in an episode would get resolved at the end, leaving a message.
Using humorous dialog and methods such as slapstick, where a character would physically get hurt or get caught into a moment which goes to far and cause disaster, normally occurs due to the characters lack of common sense. e.g. Charlie Chaplin and Buster Keaton where famous for slapstick.
Irony: Situation comedy usually uses irony
Some popular sitcoms are ones such as I love Lucy 1940s which was very popular in USA but most are famous in the UK, such as Only Fools And Horses, Blackaddar, Fawlty Towers, Dads Army.