单项选择题

有如下的程序：
#include ＜cstring.h＞
#include ＜iostream.h＞
using namespace std;
class MyString
public:
MyString(const char*s);
～MyString () delete [] data;
protected:
unsigned len;
char*data;
;
MyString::MyString(const char *s)
len=strlen (s);
data=new char[len+1];
strcpy (data,s);
int main ()
MyString a("C++ Programing");
MyString b(

点击查看答案&解析