Default values of formal arguments can be given in a function specification as part of the specification's interface. The syntax is the same as that of C++. See section 5.4.6 Function Declarations for the syntax.
For example, consider the following function specification.
// @(#)$Id: interest.lh,v 1.4 1997/06/03 20:30:08 leavens Exp $
extern float interest(float x, float rate = 0.05) throw();
//@ behavior {
//@ requires 0.0 <= rate /\ rate <= 1.0;
//@ ensures result = x * rate;
//@ }
The function interest takes two float values denoted by
rate and x respectively, and computes interest based
on rate. The default value of rate is specified to be
0.05; that is, if no value is supplied for rate on function
invocation, 0.05 is used by default.
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