Confusion about using override with constructors

Question

Since I have overridden the function returnANumber in the derived class, the constructor shall return "overridden" instead of executing the branch in the parent class. But the result is different with what I expect :\

#include <iostream>
#include <string>

using namespace std;

class NewClass {
public:
    NewClass(){
        returnANumber();
    }
    virtual void returnANumber(){
        cout << "random number blah blah blah";
    }
};

class DeriveClass : public NewClass {
public:
    void returnANumber() override {
        cout << "overridden";
        }
        };

        int main(){
            NewClass NewClass;
            DeriveClass DeriveClassInst;
            DeriveClassInst.returnANumber();
        }

Result: "random" "random" "overridden" The member function seems to be overridden at last, but it didn't work with the constructor. Expected output: "random" "overridden" "overridden"