下面程序的结果是( )。
#include<iostream.h>
class A
int a;
public:
A():a(1)
void showa()cout<<a;
;
class B
int a;
public:
B():a(2)
void showa()cout<<a;
;
class C:public A,public B
int a;
public:
C():a(3)
void showa()cout<<a;
;
void main()
C c;
c.showa();
A.1
B.2
C.3
D.程序有错误