Overloaded assignment operators

The following points should be noted:

1. Whether to declare the return value type as a reference to that type, or not to make successive assignments

2. Whether the passed parameter is declared as a constant reference , if it is not a constant, there is no guarantee that the passed argument will not be modified, and if it is not a reference, the copy constructor is called once to affect the efficiency of the Code.

3. Determines whether the two operands that are assigned are the same instance .

4. Whether to delete the memory of the assigned object, otherwise a memory leak will occur.

The program code is as follows:

#include <iostream>#include<cstring>using namespacestd;classmystring{ Public: Mystring&operator=(ConstMystring &str); Mystring (Char*pdata=null)//constructors with default values{Data=pdata; } Mystring (ConstMystring &str)//copy Constructor{Data=Str.data; }    ~mystring ()// Destructors    {    }    voidShow () {cout<<data<<Endl; }Private:    Char*data;}; Mystring&mystring::operator=(ConstMystring &str) {    if(&str!= This)//If the &str==this does not have to be assigned a value    {        DeleteData//release the original space firstData=NULL; Data=New Char[Strlen (Str.data) +1];//initializing space for pointersstrcpy (Data,str.data);//Assign Value    }    return* This;}intMain () {Mystring str1 ("Hello"), str2;//declaring two classes of objectsstr1.show (); STR2=STR1;//calling a custom assignment methodstr2.show (); STR1=STR1;//assign yourself a valuestr1.show (); return 0;}

Overloaded assignment operators