Thread: returning multiple values from functions?

There are two options. Either pass references/pointers as arguments (preferable) or create a struct that has all the variables you'd like and return it (not preferable). For example:

Code:

struct UglyStruct {
  int    some_thing;
  char   another_thing;
  string foo_bar;
};

UglyStruct some_func() {
  UglyStruct us;
  us.some_thing    = 1234;
  us.another_thing = '?';
  us.foo_bar       = "Blah";
  return us;
}

void some_func(int &int_ref, char &char_ref, string *ptr_string) {
  int_ref  = 2468;
  char_ref = '!';
  if (ptr_string != 0)
    *ptr_string = "*Cough cough*";
}

Of course it all depends entirely on context. There absolutely are cases where an individual will use a struct to group multiple variables together (I've done exactly that many a time). In fact, there are some cases where it's explicitly required (such as passing multiple params as an LPARAM in a Windows message or a void* in a child thread, for example), but I personally feel it is not a very attractive practice to create structs on-the-fly for simple situations where the struct will strictly be used for returning a pair of values. As an example, I would consider it "ugly" to do something like this:

Code:

struct RetData {
  string str;
  int    length;
};

RetData str_copy(const string &src) {
  RetData ret;
  ret.str    = src;
  ret.length = src.length();
  return ret;
}

when you could do this:

Code:

int str_copy(string &dest, const string &src) {
  dest = src;
  return dest.length();
}

or this:

Code:

void str_copy(string &dest, int &length, const string &src) {
  dest   = src;
  length = dest.length();
}

It's not that one is necessarily better than the other. Rather, in such a simple case, I feel that creating a struct strictly to return a pair of values (not to mention all the potential temporary variables that could be created) is overkill. But that's just me.