(octave.info)Default Arguments

---

Next: Function Files Prev: Returning from a Function Up: Functions and Scripts

---

Enter node , (file) or (file)node

11.8 Default Arguments
======================

Since Octave supports variable number of input arguments, it is very
useful to assign default values to some input arguments.  When an input
argument is declared in the argument list it is possible to assign a
default value to the argument like this

     function NAME (ARG1 = VAL1, ...)
       BODY
     endfunction

If no value is assigned to ARG1 by the user, it will have the value
VAL1.

   As an example, the following function implements a variant of the
classic “Hello, World” program.

     function hello (who = "World")
       printf ("Hello, %s!\n", who);
     endfunction

When called without an input argument the function prints the following

     hello ();
          ⊣ Hello, World!

and when it’s called with an input argument it prints the following

     hello ("Beautiful World of Free Software");
          ⊣ Hello, Beautiful World of Free Software!

   Sometimes it is useful to explicitly tell Octave to use the default
value of an input argument.  This can be done writing a ‘:’ as the value
of the input argument when calling the function.

     hello (:);
          ⊣ Hello, World!