C++ Language/ProgramFlow/BreakStatement/FallthroughInSwitch

A  statement is an efficient substitute for many   chains. In a  statement, each body is a sequence of statements preceded by a   label. If you don't terminate that sequence of statements by, then program flow will fall-through and also perform the next sequence of statements. This is often a programming bug, so when you intentionally do this, write  in place of.

Additional information about fallthrough (includes interactive examples)