How to initialize base class members in Inheritance

Question

Hi.I want to initialize the variables of base class in derived class:

class Base{
public:
int val = 10;
virtual void print(){cout << "Base class\n";}
};

class derived1: public Base{
public:
void print(){cout << "derived1 class\n";}
};

How can I change val in derived1 to 5?