C++实现String类实例代码

#include 
using namespace std; 
 
class String 
{ 
public: 
    String(const char *str=NULL); 
    String(const String &other); 
    ~String(void); 
    String &operator =(const String &other); 
private: 
    char *m_data; 
}; 
 
String::String(const char *str) 
{ 
  cout<<"构造函数被调用了"<