I want to understand how typecast-overloading works. For my question, I want to know

1. The thing I'm trying to do is it possible?
2. If yes, then how?

I want the user to be able to pass a vector<float> to a function. This function is implemented in such a way that its parameter is a wrapper class around vector<float>.

Can typecast-overloading help in such a case? (automatically convert vector<float> into Layer) or do we have to use some complicated templated function?

// ---------- someFile.cpp ------------
class Layer {
    vector<float> l;
  public:
    friend void process (const Layer& someLayer);
}
// ---------- main.cpp ------------
int main() {
    vector<float> vec = {1.0, 1.5, 2.0};
    process(vec);
}

CodePudding user response：

All that's needed is a non-explicit constructor taking the correct argument (a so-called conversion constructor):

class Layer {
    vector<float> l;

public:
    Layer(vector<float> const& v);
};

Now the compiler will be able to do implicit conversions from vector<float> to Layer.

Note that it's usually not recommended to have such conversion constructors being non-explicit (not declared using the explicit keyword), because sometimes implicit conversions might be unexpected and not wanted.