CODEWITHSUNDEEP
c++memory-leakscontainers
Vinícius
Vinícius

Reputation: 15756

objects inserted into containers must be cleared at the destructor?

Suppose:

struct Foo
{
    int _b;
    std::string _name;
};

class Bar
{
public:
    vector<Foo>hold;
};

If a call to hold.clear() isn't done on the destructor, does it means a memory leak? I'm talking about objects, not pointer, because as far as I know push_back creates a copy of the original object;

Upvotes: 0

Views: 70

Answers (2)

sylvain.joyeux
sylvain.joyeux

Reputation: 1699

When an object is destroyed, so is all its members. So the (automatically generated) destructor of Bar will call the destructor of its hold member, which is going to call the destructors of its elements.

In summary: everything is destroyed automatically. This is a guarantee in C++: if you are manipulating objects by value, you have the guarantee that they are going to be destroyed when they get out of scope. The only thing you have to destroy explicitly are the objects that have been allocated on the heap (i.e. using new).

Upvotes: 1

juanchopanza
juanchopanza

Reputation: 227618

No, there are no memory leaks. When a Bar goes out of scope, it's data member hold is destroyed, and because std::vector is well designed, all the elements it holds are destroyed.

struct Foo
{
    int _b;
    std::string _name;
    ~Foo() { std::cout << "Foo destructor"; }
};

class Bar
{
public:
    vector<Foo>hold;
};

int main()

{

  {
    Bar b;
    b.hold.push_back(Foo());
  } // Foo, vector<Foo> and b instances destroyed here

}

Upvotes: 1

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