A procedure identifier, followed in parentheses by a list of actual parameters (if any), is known generally as a procedure call. If the procedure possesses a value, it may be used as a primary in an expression, but whether it possesses a value or not, it may also stand alone as a statement. This causes
the formal parameters in the procedure declaration to be replaced by the actuals in a manner which depends on the formal parameter specifications (see Section 8.3).
the procedure body to be executed before the statement dynamically following the procedure statement is obeyed.
The syntax for a procedure call is
Id ( Actuallist )
Actual , Actuallist
The purposes of the four types of actual parameter are defined in Section 8.3.