1 问题
实现c++的单例模式，这里测试分别写了通过智能指针返回对象和普通返回指针
2 代码测试
include <iostream>
#include <mutex>
#include <memory>using namespace std;class Single
{
public:static Single& getInstance(){std::mutex mt;if (instance.get() == NULL) {mt.lock();if (instance.get() == NULL) {instance.reset(new Single());}mt.unlock();}return *instance;}
private:Single(){}~Single(){}static std::auto_ptr<Single> instance;friend class std::auto_ptr<Single>;Single(const Single&);Single& operator= (const Single&);
};std::auto_ptr<Single> Single::instance;class Single1
{
public:static Single1* getInstance(){mutex mt;if (instance == NULL) {mt.lock();if (in
)
)
