Default Argument

When I write define of function or method with C++, I always write next code.

namespace my{
 enum Type{
  NONE = 0x00,
  SCALAR = 0x01,
  VECTOR = 0x03,
 };
 void function(double* , Type type = NONE);
}

I want that user of my function understand the function more easily than next code.

namespace my{
 enum Type{
  NONE = 0x00,
  SCALAR = 0x01,
  VECTOR = 0x03,
 };
 void function(double* , Type type);
 void function(double*);
}

Above code is the same as before function used default argument.

Using Default argument, Code line decreases.