C + + destructor

This article address: http://www.cnblogs.com/archimedes/p/cpp-destructor.html, reprint please indicate source address

Function: Perform cleanup work before destroying objects

Format:

[Class Name::]~ class name ()

{

....

}

classstudent{ Public: Student (...); ~student ();//~ Symbol    voidDisplay ()Const;Private:    intM_inum; stringM_strname; CharM_csex; }; Student::~Student () {cout<<"destructor"<<Endl;} ...

Attention:

The function name is the same as the class name, and the number of functions is pre-added ~

No parameters, cannot be overloaded

Do not specify a return value

often defined as public

Automatic invocation at end of object lifetime

Thinking:

Usually there is no need to define destructors, when do you have to define destructors?

In general, when a class contains a pointer member, and the pointer points to memory in a heap in the constructor, you must define the dynamic space that the destructor should release for that pointer request

#include <iostream>using namespacestd;classstring{ Public: String (); voidDisplay ()Const;Private:     Char * m_pstr;}; String::string () {m_pstr= New char[  +]; strcpy (M_pstr,"Hello");}voidString::d isplay ()Const{cout<<m_pstr<<Endl;}/*string::~string () {//system-generated}*/intMain () {String str;    Str.display (); System ("Pause"); return 0;} 

Look at the following code, using the destructor of your own definition--example code 1:

#include <iostream>using namespacestd;classstring{ Public: String (); ~String (); voidDisplay ()Const;Private:    Char*M_pstr;}; String::string () {m_pstr=New Char[ +]; strcpy (M_pstr,"Hello");} String::~String () {delete []m_pstr;}voidString::d isplay ()Const{cout<<m_pstr<<Endl;}intMain () {String str;    Str.display (); System ("Pause"); return 0;} 

Example code 2:

#include <iostream>using namespacestd;classstring{ Public: String (Char*ap =" China"); ~String (); voidDisplay ()Const;Private:    Char*M_pstr;}; String::string (Char*AP) {M_pstr=New Char[Strlen (AP) +1]; strcpy (M_PSTR, AP);} String::~String () {delete []m_pstr;}voidString::d isplay ()Const{cout<<m_pstr<<Endl;}intMain () {String str1 ("USA");    Str1.display ();    String str2;    Str2.display (); System ("Pause"); return 0;} 

If you want to define destructors, you often need to define overloaded functions for copy constructors and assignment operators. For copy constructors, refer to the C + + copy constructor

C + + destructor