insert in a vector of vector

[danadam]

vector < vector <double> > temp;
temp.resize(_set->size());	
vector < vector <double> >::iterator iit=temp.begin();

vector < vector <double> > temp;
temp.resize(_set->size());	
vector < vector <double> >::iterator iit=temp.begin();

To copy to clipboard, switch view to plain text mode 

What is this iterator for? You only increase it in your loop, but you don't use it anywhere.

int i=0;
vector < vector <double> >::iterator itra = _set->begin();	
srand ((unsigned)time(NULL));
while ( ! _set->empty() )  {
	do {
		i = rand() % (int) _set->size();
		cout << " i " << i << endl; 
		if (i == 0 &&  _set->size() == 1) break;
	} while (i >= (int) _set->size() || i == 0);

int i=0;
vector < vector <double> >::iterator itra = _set->begin();	
srand ((unsigned)time(NULL));
while ( ! _set->empty() )  {
	do {
		i = rand() % (int) _set->size();
		cout << " i " << i << endl; 
		if (i == 0 &&  _set->size() == 1) break;
	} while (i >= (int) _set->size() || i == 0);

To copy to clipboard, switch view to plain text mode 

These conditions are redundant, I guess. By using % operator variable "i" takes value from interval 0 (incl), set->size()(excl). So if size is 1 then it's no use checking if "i" is zero. Additionally variable "i" will never be greater or equal then set->size().

temp.insert (temp.begin(), itra+i, itra+i); 	//here it is filling nothing

temp.insert (temp.begin(), itra+i, itra+i); 	//here it is filling nothing

To copy to clipboard, switch view to plain text mode 

These two iterators points the same element. insert() method insert sequence from first(incl) to last(excl), so in your case it inserts nothing. Try to pass the last argument as itra+i+1.