Is the constructor called immediately for an array of objects as a member of the class?

Question

class gene{
    int ind;

    gene() {
        ind = 0;
    }
}

class network {
    gene g[10];
}

main() {
    network n;
}

Should I call the constuctor for each object in the g array, or it will be called automatically?

e.g, should I change the network class as follows:

class network {
    gene g[10];

    network() {
        for(int i = 0; i < 10; i++)
            g[i] = gene();
    }
}

Answer 1

In your case, because gene has a non-trivial default constructor, each element of the array will be default-constructed for you. I.e., no, your change is unnecessary.

In the circumstance that your array's underlying type is a POD type, you will need to initialize the elements manually. However, the way you're doing it is not ideal; you would want to use value-initialization instead:

class network {
    somePodType x[10];
public:
    network() : x() { }
};