C + + Singleton mode

#include <iostream> #include <string>using namespace Std;class signalexample{static signalexample* c_ instance;//all constructors (constructors, copy constructs, assignment overloads) are privatized so that external objects cannot be created directly signalexample () {}signalexample (); Signalexample (const signalexample&); signalexample& operator = (const signalexample&);//Create a static privatized member to store a unique singleton object public://static functions for creating unique singleton objects Must be public static so that the static signalexample* getinstance () is called directly before the object is created, void print ();//The detection function for printing object addresses}; signalexample* signalexample::c_instance = NULL; signalexample* signalexample::getinstance () {///If an object has already been created, then return directly, if not, call the constructor if (c_instance = = NULL) {c_instance = new Signalexample ();} return c_instance;} void Signalexample::p rint () {cout<< "address-->this:" &LT;&LT;THIS&LT;&LT;ENDL;}    int main () {signalexample* s = signalexample::getinstance ();    signalexample* S1 = signalexample::getinstance ();    signalexample* s2 = signalexample::getinstance ();    S->print ();    S1->print ();    S2->print (); return 0;}

　　

#include <iostream> #include <string> #include "Singleton.h" using namespace Std;class signalexample{Friend Class singleton<signalexample>;//privatize all constructors (constructors, copy constructs, assignment overloads) so that external objects cannot be created directly signalexample () {}signalexample ( Const signalexample&); signalexample& operator = (const signalexample&);//Create a static privatized member to store only one singleton object public:void print ();//    Detection function for printing object addresses};class Test{private:friend class singleton<test>; Test () {} test (const test&) {} test& operator = (const test&);p ublic:void print ();//For Print object address detection function};void test::p rint () {cout<< "address-->this:" &LT;&LT;THIS&LT;&LT;ENDL;} void Signalexample::p rint () {cout<< "address-->this:" &LT;&LT;THIS&LT;&LT;ENDL;}    int main () {signalexample* s = singleton<signalexample>::getinstance ();    signalexample* S1 = singleton<signalexample>::getinstance ();    signalexample* s2 = singleton<signalexample>::getinstance (); test* S4 = Singleton<test>:: getinstance ();    test* s3 = Singleton<test>::getinstance ();    S->print ();    S1->print ();    S2->print ();    S3->print ();    S4->print (); return 0;}

　　

#ifndef _singleton_h_#define _singleton_h_template< TypeName T >class singleton{    static t* c_instance;public :    static t* getinstance ();}; template< typename t >t* singleton<t>::c_instance = null;template< typename T >t* singleton<t>:: GetInstance () {    if (c_instance = = NULL)    {        c_instance = new T ();    }    return c_instance;} #endif

　　

C + + Singleton mode