阅读该程序，给出程序的输出结果。
#include <iostream.h>
class A
{
public:
A(int i,int j)
{
a1=i;
a2=j;
}
void Print()
{
cout<<a1<<','<<a2<<endl;
}
private:
int a1,a2;
};
class B
{
public:
B() : b(0)
{
}
B(int i) : b(i)
{
}
void Print()
{
cout<<b<<endl;
}
private:
int b;
};
class C: public A
{
public:
C(int i,int j,int k,int l):A(i,j),c(l)
{
}
void Print()
{
A::Print();
b.Print();
cout<<c<<endl;
}
private:
B b;
int c;
};
void main()
{
A a(7,8);
a.Print();
B b(9);
b.Print();
C c(4,5,6,7);
c.Print();
}
