how to use a setter for vector of an object

Question

std::vector<Game*> games;

I have the following setter:

void Instructor::setGames(const std::vector<Game *> &value)
{
    games = value;
}

And I am trying to use it like this:

 Game g1, g2, g3;
std::vector <Game> gameSet;
    gameSet.push_back(g1);
    gameSet.push_back(g2);
    gameSet.push_back(g3);
    i.setGames(&gameSet);

But I keep getting this error:

error: no matching function for call to ‘Instructor::setGames(std::vector<Game>*)’
     i.setGames(&gameSet);

This doesn't work either.

 i.setGames(gameSet);

What am I doing wrong? I want to fix this without changing the std::vector<Game*> games;

Ah but when I change ```std::vector gameSet;``` to ``````, I get errors on push_back even if I use a reference @PeterT — x89, May 02 '20 at 22:57
The question is what is `games`, is it `std::vector` or a `std::vector`? — anastaciu, May 02 '20 at 22:58

anastaciu · Accepted Answer · 2020-05-03T13:34:56.143

1

Given that you have a vector of Game pointers, that is the type of object it will accept, therefore g1, g2 and g3 must be pointers:

Game *g1, *g2, *g3;
std::vector <Game*> gameSet;

g1 = new Game(); //intialize pointers
g2 = new Game();
g3 = new Game();
//...
i.setGames(gameSet);

Live demo

Note that using raw pointers is not really a good practice these days, it's best to use smart pointers, look into that.

What is a smart pointer and when should I use one?

edited May 03 '20 at 13:34

answered May 02 '20 at 23:01

anastaciu

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that gives me a segmentation fault core(dump) – x89 May 02 '20 at 23:09
@FSJ, I made you a live demo, add it to the answer, hope it helps. – anastaciu May 02 '20 at 23:24

score 0 · Answer 2 · answered May 02 '20 at 23:00

The

i.setGames(&gameSet);

needs setGames taking pointer to the std::vector<Game>. That means the following function signature

void Instructor::setGames(std::vector<Game> *value);

what you have is const ref to simple std::vector<Game*>

void Instructor::setGames(const std::vector<Game*> &value);

Obviously they are different types and you have the error.

You need simply const std::vector<Game>& value

void Instructor::setGames(const std::vector<Game>& value)
{
    games = value; // also change the type of games  to be std::vector<Game>
}

and in the main

  Game g1, g2, g3;
  std::vector <Game> gameSet{ g1, g2, g3};
  i.setGames(gameSet);

Is there no way to fix this without changing ``` std::vector games;``` ? — x89, May 02 '20 at 23:09
@FSJ Okay, then the following is the answer. Along with ` i.setGames(gameSet);`. But you don't need ` std::vector`. — LernerCpp, May 02 '20 at 23:11

how to use a setter for vector of an object

2 Answers2