C++对象参数与返回

 class String
{
  public:
  String(const char *str=NULL);
  String(const char &other);
  ~String(void);
  String & operate=(const String &other);
  private:
  char *m_data;
};
String::~String(void)
{
  delete []m_data;
 }
//构造
String::String(const char *str)
{
  if (str==NULL)
   {
     m_data=new char[1];
     *m_data='/0';
   }
   else
    {
      int length=strlen(str);
      m_data=new char[length+1];
      strcpy(m_data,str);
    }
}
//拷贝
String::String(const String &other)
{
  int length=strlen(other.m_data);
  m_data=new char[length+1];
  strcpy(m_data,other.m_data);
 
}
//赋值函数
String & String::operate=(const String &other)
{
 if(this==&other)
  return *this;
delete [] m_data;
int length=strlen(other.m_data);
m_data=new char[length+1];
strcpy(m_data,other.m_data);
return *this;
}

void main()
{
  String s1("hello");
  String s2=s1;
  String s3("hello");
  String s4=("like");
  s3=s4;
  cout<<*(s1.m_mata)