oj C++继承（改错题）

#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{protected:    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;}

感悟：cllass A少写了一个“；”，竟然提示class B没写“；”，为啥啊！