Jz-c-01

The sword refers to the offer code realization: Basic knocks, by the way write comments and questions.

First question: Add an assignment operator function to the CMyString class with the following code:

1 //============================================================================2 //Name:jz-c-01.cpp3 //author:laughing4 //Version:5 //copyright:your Copyright Notice6 //Description:hello World in C + +, Ansi-style7 //============================================================================8#include"stdafx.h"9#include <string.h>Ten using namespacestd; One /** A * Sword refers to the offer surface question 1 -  */ - classcmystring { the  Public: -CMyString (Char* PData = NULL);//constructor Function -CMyString (ConstCMyString &str);//like a copy constructor?  -~cmystring (void); +     voidPrint ();//Print -cmystring&operator=(ConstCMyString &str);//assignment operator Overloading: The return type is a reference to the type so that successive assignments can be allowed: "STR=STR1=STR2". Const: Because the state of an incoming instance is not changed within an assignment operator function + Private: A     Char*m_pdata; at }; -Cmystring::cmystring (Char*pData) { -     if(PData = = NULL) {//if it is empty -M_pdata =New Char[1]; -M_pdata =' /';//string Default last fill ' \ ' -}Else { in         intLength = strlen (PData);//string Length -M_pdata =New Char[Length +1];//why +1? tostrcpy (M_pdata, pData);//Copy +     } - } theCmystring::cmystring (ConstCMyString &str) { *     intLength =strlen (str.m_pdata); $M_pdata =New Char[Length +1];Panax Notoginseng strcpy (M_pdata, str.m_pdata); - } thecmystring::~cmystring () { +     Delete[] m_pdata;//Freeing Memory A } the voidcmystring::p rint () { +cout << m_pdata <<Endl; - } $cmystring& cmystring::operator=(Constcmystring& str) {//automatic generation, with inline in front, why?  $     if( This= = &str) {//first determine if the parameter passed in and the current instance is not the same instance ★ -         return* This; -     } the     /*If there is no above if judgment, if the same instance, once the memory of the release itself, the memory of the passed parameter is also released*/ -     Delete[] m_pdata;//Free Memory FirstWuyiM_pdata =NULL; theM_pdata =New Char[Strlen (Str.m_pdata) +1];//Reassign Space - strcpy (M_pdata, str.m_pdata); Wu     return* This;//returns a reference to the instance itself - } About intMain () { $cout <<"Hello World!!!"<< Endl;//prints Hello World!!! -     Char* str ="Hello World";//What's the problem, and not the const difference - cmystring Test (str); - test.print (); A cmystring test2, test3; +     //test = test;//assign to yourself, here to determine whether the incoming parameter and the current instance will not have the same problem theTest3 = Test2 = Test;//Assigning a value to an object test2,test3 using an assignment operator - test3.print (); $     return 0; the}

Jz-c-01