Answers for "c++ call parent constructor"

c++ base constructor

class Derived: public Base
{
public:
    double m_cost;
 
    Derived(double cost=0.0, int id=0)
        : Base{ id }, // Call Base(int) constructor with value id!
            m_cost{ cost }
    {
    }
 
    double getCost() const { return m_cost; }
};

c++ accessing parent class functinons

class left {
public:
    void foo();
};

class right {
public:
    void foo();
};

class bottom : public left, public right {
public:
    void foo()
    {
        //base::foo();// ambiguous
        left::foo();
        right::foo();

        // and when foo() is not called for 'this':
        bottom b;
        b.left::foo();  // calls b.foo() from 'left'
        b.right::foo();  // call b.foo() from 'right'
    }
};