How could I assign values to c++ vector

I know that I can initialize a vector like this:

vector<int> v{1,3,4,6};

However, when I define a class which contains a vector, I cannot initialize it in the position that I declare it, like this:

class C {
  public: 
    vector<int> v; 
    C();
};

Thus I need to initialize it in the construction function. The following code works, but is not clean:

C::C() {
    v.resize(4); 
    v[0]=1; 
    v[1]=3; 
    v[2]=4; 
    v[3]=6;
}

How could I initialize it neatly and directly like vector<int> v{1,3,4,6}; rather than assign values one by one ?

Edit: Maybe I have not make my situation clear. The value of {1,3,4 6} may not be predefined values, they would depend on some logic and conditions: if(condition_a) {v[0] = 0; v[1]=3; ...} else {v[0]=4;v[0]=8;...}. Thus I have to deal with some other things to know how to initialize this vector, so I cannot use initialization list as suggested in some answers. Any advice please?