OJ （一）B

#include <iostream>
using namespace std;
class A
{
protected:
    int a,b;
public:
    A(int aa, int bb):a(aa),b(bb){}
    void printA()
    {
        cout<<"a: "<<a<<" b: "<<b<<endl;
    }
};
class B: public A
{
    int c;
public:
    B(int aa, int bb, int cc):A(aa,bb),c(cc){}
    void printB()
    {
        cout<<"a: "<<a<<" b: "<<b<<" c: "<<c<<endl;
    }
};
int main()
{
    int a1, a2;
    int b1, b2, b3;
    cin>>a1>>a2;
    cin>>b1>>b2>>b3;
    A a(a1,a2);
    B b(b1,b2,b3);
    a=b;
    a.printA();
    b.printB();
    return 0;
}