I have a class with a private vector of doubles. To access or modify these values, at first I used methods such as

void classA::pushVector(double i)
{
this->vector.push_back(i);
}
double classA::getVector(int i)
{
return vector[i];
}

This worked for a while until I found I would have to overload a lot of operators for what I needed, so I tried to change it to get and set the vector directly instead of the values, i.e.

void classA::setVector(vector<double> vector)
{
this->vector = vector;
}
vector<double> classA::getVector()
{
return vector;
}

Now, say there is a classB, which has a private classA element, which also has get and set methods to read and write. The problem was when I tried to push back a value to the end vector in classA.

void classB::setFirstValue(double first)
{
this->getClassA().getVector().push_back(first);
}

This does absolutely nothing to the vector. It remains unchanged and I can't figure out why... Any ideas?