Maxium number of values returnable by single fucntion ?

How many values can a function return ?

I have a function which accepts several pointers. It's return type is int*

If I had the following would both be returned ?

      (*value01)++;
      return value01;
      (*value02)++;
      return value02;

Or do I even need to specify a return type because the pointers would be changed whether I returned them or not ?

Thanks.
andyw27Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Infinity08Commented:
>> If I had the following would both be returned ?

No, you can only return one parameter. So, this code :

      (*value01)++;
      return value01;    //  <---- value01 will be returned
      (*value02)++;       // <----- this will never be executed
      return value02;    // <----- this will never be executed

There are several ways to return multiple values. Here are a few :

1) pass by pointer :

        void fun(int *value01, int *value02) {
            (*value01)++;
            (*value02)++;
            return;
        }

    call it like this :

         int val1 = 1;
         int val2 = 2;
         fun(&val1, &val2);
         // val1 now has value 2
         // val2 now has value 3

2) pass by reference :

        void fun(int &value01, int &value02) {
            value01++;
            value02++;
            return;
        }

    call it like this :

         int val1 = 1;
         int val2 = 2;
         fun(val1, val2);
         // val1 now has value 2
         // val2 now has value 3

3) return a struct :

        struct retvals {
            int val1;
            int val2;
        }

        retvals fun(retvals vals) {
            (vals.val1)++;
            (vals.val2)++;
            return vals;
        }

    call it like this :

         retvals vals = { 1, 2 };
         vals = fun(vals);
         // vals.val1 now has value 2
         // vals.val2 now has value 3
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
andyw27Author Commented:

Thanks thats a great answer.
0
AlexNekCommented:
As it is C++ I would suggest to create a class like
class CCounters
{
public:
   CCounters(): m_Value1(0), m_Value2(0) {}
    void IncValue1() {m_Value1++;}
    void IncValue2() {m_Value2++};
    void IncAll() {IncValue1(); IncValue2();}
private:
   int  m_Value1;
   int M_Value2;
}
...
CCounters Counters;
..
func(Counters);

...
void func(CCounter& rCounters)
{
....
  rCounters.IncAll();
}
0
Cloud Class® Course: Microsoft Office 2010

This course will introduce you to the interfaces and features of Microsoft Office 2010 Word, Excel, PowerPoint, Outlook, and Access. You will learn about the features that are shared between all products in the Office suite, as well as the new features that are product specific.

MacroLandCommented:
or another function could be like;

int* returnSomething(int* p1,int* p2)
{
  int* ret=new int[5];
  p1++;
  p2++;

  for (int i=0;i<5;i++)
     *(ret+i)=i;

  return ret;

}

Here both p1 and p2 is modified and you also get five different value, or as much as you can

To use it;

int main()
{
   x=5;y=7;
   int* pf=returnSomething(&x,&y);

  //now x and y are both incremented
  for (int i=0;i<5;i++)
    std::cout<<*(pf+i)<<std::endl;

return
}

Regards,
0
AlexNekCommented:
In addition you have the memory leak.
I'm sorry, but the last suggestion I would be never recommended because it is a "dirty" solution.
I think the answer coud be:
The function can return only one value as return. This value can be a value, a pointer or a reference.

So we can return the complex object and this object can hold as many values as we need.
0
MacroLandCommented:
>>In addition you have the memory leak.

int main()
{
   x=5;y=7;
   int* pf=returnSomething(&x,&y);

  //now x and y are both incremented
  for (int i=0;i<5;i++)
    std::cout<<*(pf+i)<<std::endl;

    delete pf; //delete the memory pointed by pf

    return 0;
}

Would you still have the memory leaks?
0
AlexNekCommented:
In this case not any more but in real project it is very easy to forget it.
0
itsmeandnobodyelseCommented:
>>>  but in real project it is very easy to forget it.
Yes, normally you should delete a pointer where you created it. Only *create* functions where the only purpose is to create a new pointer are an exception from above rule. In a class you should store newly created pointers (if there is a need for pointers at all) in a data member and delete in the destructor.

Regards, Alex
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
C++

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.