单项选择题

有以下程序
#include ＜iostream＞
using namespace std:
class Baseprivate:
char c;
public:
Base(char n) :c(n)
～Base ( )

cout＜＜c;

;
class Derived : public Baseprivate:
char c;
public:
Derived(char n):Base(n+1),c(n)
～Derived()

cout＜＜c;

;
int main() Derived obj('x');
return 0; 执行后的输出结果是