Remove elements of a vector inside the loop

Question

I know that there are similar questions to this one, but I didn’t manage to find the way on my code by their aid. I want merely to delete/remove an element of a vector by checking an attribute of this element inside a loop. How can I do that? I tried the following code but I receive the vague message of error:

'operator =' function is unavailable in 'Player’.

 for (vector<Player>::iterator it = allPlayers.begin(); it != allPlayers.end(); it++)  {      if(it->getpMoney()<=0)           it = allPlayers.erase(it);      else           ++it;  } 

What should I do?

Update: Do you think that the question vector::erase with pointer member pertains to the same problem? Do I need hence an assignment operator? Why?

Answer 1

You should not increment it in the for loop:

for (vector<Player>::iterator it=allPlayers.begin();                                it!=allPlayers.end();                                /*it++*/) <----------- I commented it. {     if(it->getpMoney()<=0)        it = allPlayers.erase(it);   else        ++it;  } 

Notice the commented part;it++ is not needed there, as it is getting incremented in the for-body itself.

As for the error "'operator =' function is unavailable in 'Player’", it comes from the usage of erase() which internally uses operator= to move elements in the vector. In order to use erase(), the objects of class Player must be assignable, which means you need to implement operator= for Player class.

Anyway, you should avoid raw loop¹ as much as possible and should prefer to use algorithms instead. In this case, the popular Erase-Remove Idiom can simplify what you're doing.

allPlayers.erase(     std::remove_if(         allPlayers.begin(),          allPlayers.end(),         [](Player const & p) { return p.getpMoney() <= 0; }     ),      allPlayers.end() );  

^{1. It's one of the best talks by Sean Parent that I've ever watched.}