6 Cast operator overloading

Type casting is an operator. In other words, (float) of (float)23 is an unary operator. As with other operators, cast operator can be overloaded as well.

There is really not much to say about cast operators, except that their declaration is a little different. Let's use the following example:

class X
{
    int i,j;
  public:
    // ...
    operator float (void);
};

The only member function is operator float (void). Unlike other operators, which require a specification of the return type, cast operators have their return type implied by the operator itself. As a result, the cast operator to convert to float has an implied return type of float. The (void) part is just to specify the operator has no parameters.

The definition of this operator may look like the following:

X::operator float(void)
{
  return (float)i/j;
}

The use of the operator is illustrated by the following example:

{
  X var1;

  printf("%f\n", (float)var1);
}