Thread: Can a function return an interator to main()

....and if so what is the function defination then to be ?

I just want my self written function (sort) which sorts lists to return me a pointer after its execution so that i can perform tasks on the sorted list IN THE FUNCTION MAIN(); (dont ask why...i just want to cause i cant control my urge to do it otherwise which stems out of the fact that i cannot do it as of now)

so i wondered that since iterators are kind of pointers can i simply return them ?

Thanks all..

LOL...i think its safe to assume that the answer is blowing in the wind and the answer is NO

Originally Posted by brewbuck

More seriously, why do you think main() is different from any other code? There's no restriction on what you can do inside main().

i know but then i was planning onto writting special functions for each tasks that i would be performing on the sorted list.Hence......thanks though for ruining my dream of wanting to return an iterator to main()

What...the answer is yes you say....what would be the function declaration of such a function returning an iterator ?

eg:

(what should be here) IAM_A_Function_Returning_ITERATOR( int, int)

What the hell are you talking about?

I would suppose that main is the entry point of your program and it should get called only once during program execution. That is, you don't ever call main yourself.

Whatever you mean by interator to main, you are probably not supposed to use it in any way, so there's no point returning it.

Perhaps post your real problem but keep in mind that calling main on something in a linked list is not a good idea.

grrrrrrrr....my bad...ok heres an example code ..i am not attempting to call main() as brewbuck guessed..my bad if the post is confusing..infact I am in elementary school as brewbuck guessed right yet again..

Code:

#include<iostream>
#include<list>

using namespace std;

class RandomClass
{
	private:
		int xyz;
	public:
		void Make_A_List(RandomClass *);
};

int main()
{
	RandomClass temp;
	temp.Make_A_List(&temp);

	return 0;
}

void RandomClass::Make_A_List(RandomClass *p)
{
	list<RandomClass> ListOfInts;
	list<RandomClass>::iterator it;
	int input;

	cout << "Enter the integer : "<< endl;
	cin >>input;
	p->xyz=input;
	ListOfInts.push_back(*p);

	for(it= ListOfInts.begin();it!=ListOfInts.end();it++)
		cout<<it->xyz<<endl;	
}

now what if i want to add another line at the end of Make_A_List function...

Code:

return it ; // "it" is the iterator

in that case i need to get rid of the void preceding the function prototype...but what takes the place of void then....that is my question.

Well, for one thing, you would be returning an iterator to a local list that is destroyed at the end of the function. That is a Bad Thing.

What problem are you trying to solve?

ohh lord...so true...your post laserlight dawns on me like an epiphany..the list will be destroyed as soon as control hops out of the function...
well i am not trying to solve any particular problem...i just had this question if iterators can be returned.Brewbuck did say one can but i havent quite gotten it it..thanks to my noob brain

So in the above example if i were to declare the list as global by making the follwing change to the above code

Code:

class RandomClass
{
	private:
		int xyz;
	public:
		void Make_A_List(RandomClass *);
}temp ;

can i then simply return the iterator as mentioned in the previous post and if yes then what is the function prototype of the Make_A_List function

That does not make the list global, but makes a global RandomClass object. You probably do not even need globals at all, but perhaps the list should be passed by reference.

ok thanks....let me put an end to this as of now...i think i need some more reading about STL...will do that first and if i still have got the same question left unanswered then i will post here again....



thanks all