9 Statements [stmt.stmt]

9.2 Expression statement [stmt.expr]

Expression statements have the form
All side effects from an expression statement are completed before the next statement is executed.
An expression statement with the expression missing is called a null statement.
Most statements are expression statements — usually assignments or function calls.
A null statement is useful to carry a label just before the } of a compound statement and to supply a null body to an iteration statement such as a while statement.
end note