Identification of copy constructor and value assignment function

(1) test yourself. can you differentiate it?

String A ("zhangbufeng ");
String B ("cuixiaoyuan ");
String C (a); // when creating an object, use the copy constructor.
C = B; // C has been initialized and the value assignment function is called. The last time I wrote more strings, the definition was redefined.

 

(2) code verification

 

 

# Include <iostream>
# Include <string>
Using namespace STD;

Class string
{
Public:
String (const char * STR = NULL); // common Constructor
String (const string & other); // copy the constructor
~ String (void); // destructor
String & operator = (const string & other); // value assignment function
PRIVATE:
Char * m_string; // Private member, saving the string
};
String ::~ String (void)
{
Cout <"destructing" <Endl;
Delete [] m_string;

}

String: string (const char * Str)
{
Cout <"construcing" <Endl;
If (STR = NULL)
{
M_string = new char [1];
* M_string = '/0 ';
}
Else
{
Int length = strlen (STR );
M_string = new char [Length + 1];
Strcpy (m_string, STR );
}
}
String: string (const string & other)
{
Cout <"constructing copy" <Endl;
Int length = strlen (other. m_string );
M_string = new char [Length + 1];
Strcpy (m_string, other. m_string );
}
String & string: Operator = (const string & other)
{
Cout <"operate = function" <Endl;

// Check auto-assigned values
If (this = & other)
Return * this;
 
// Release the original memory resource
Delete [] m_string;

// Allocate new memory resources and copy the content
Int length = strlen (other. m_string );
M_string = new char [Length + 1];
Strcpy (m_string, other. m_string );

// Return the reference of this object
Return * this;
}
Void main ()
{
String A ("zhangbufeng ");
String B ("cuixiaoyuan ");
String C ();
C = B;
String d =;
}