阅读下列程序，写出运行结果： #include

#include<iostream>
using namespace std;
class A
{
public:
A(int x):a(x=0){ }
void getA(int &A) { A=a; }
void printA() { cout<<"a="<<a<<endl; }
private:
int a;
};
class B
{
public:
B(int x, int y):aa(x=0) { b = y; }
void getAB(int &A, int &outB) { aa.getA(A); outB=b; }
void printAB() { aa.printA(); cout<<"b="<<b<<endl; }
private:
A aa;
int b;
};
int main()
{
A objA;
int m=5;
objA.getA(m);
cout<<"objA.a="<<m<<endl;
cout<<"objB:\n";
B objB;
objB.getAB(12,56);
objB.printAB();
}