The second-order tectonic mode of C + +

Foreword: in C + +, a bug is often caused by a failure to invoke system resources, so a bug occurs when the class calls the constructor to allocate system resources, causing the class object to be created, but only semi-finished, in order to avoid the need to use the second construction mode

　　　　　　　　　　　　　　　　　　　　　　Second-order tectonic mode

The source code is as follows

1 //second-order construction. CPP: The entry point that defines the console application. 2 //3 4#include"stdafx.h"5#include <iostream>6 7 using namespacestd;8 9 classTestTen { One Private: A     intD; -Test ();//first-order construction, construction of operations that do not generate a bug assignment, etc. -     BOOLConstruct ();//second-order construction, construction application system resources, memory application the  Public: -     //static functions, ingenious in that static functions can access private members -     //and no object is required to invoke -     Statictest* newinstance ();//Total Constructors + }; -  + intMain () A { atTest *p =test::newinstance (); -  -cout << P <<Endl; -  -     return 0; - } in  - //first-order construction, construction of operations that do not generate a bug assignment, etc. to test::test () + { -  the } *  $ //second-order construction, construction application system resources, memory applicationPanax Notoginseng BOOLtest::construct () - { the     return 1; + } A  the //Total Constructors +test*test::newinstance () - { $Test *ret =NewTest//first-order construction $  -     //first-order allocation failure or second-level allocation failure -     //Delete the semi-finished object and place the empty the     if(! (ret&&ret->construct ())) -     {Wuyi         Deleteret; theRET =NULL; -     } Wu  -     returnret; About}

The second-order tectonic mode of C + +