懒汉式:需要时才构造该单例
class CRemoteControl
{
public:
~CRemoteControl(void){ }
static CRemoteControl& GetInstance()
{
if(m_rc == NULL)
m_rc = new CRemoteControl();
return m_rc;
}
private:
CRemoteControl(void)
{
cout << "CRemoteControl构造函数" << endl;
}
private:
static CRemoteControl* m_rc;
};
CRemoteControl* CRemoteControl::m_rc = NULL;
饿汉式:
class CRemoteControl
{
public:
~CRemoteControl(void){ }
static CRemoteControl& GetInstance()
{
return m_rc;
}
private:
CRemoteControl(void)
{
cout << "CRemoteControl构造函数" << endl;
}
private:
static CRemoteControl* m_rc;
};
//静态成员变量与全局变量一样,在编译期间分配内存,即在声明类对象之前创建,即在函数运行之前分配内存
CRemoteControl* CRemoteControl::m_rc = new CRemoteControl();
课题组使用的饿汉式:没有使用指针,而是使用了static局部变量
class CRemoteControl
{
public:
~CRemoteControl(void){ }
//返回引用和返回对象的原则:不能返回局部对象的引用;其余均可以也应该返回引用。
static CRemoteControl& GetInstance()
{
//对局部变量用static声明,把它分配在静态存储区,变量在整个程序执行期间不释放,其所分配的空间始终存在
//对全局变量用static声明,则该变量的作用域只限于本文件模块
static CRemoteControl remoteControl;
cout << &remoteControl << endl;//始终是同一个变量
return remoteControl;
}
private:
CRemoteControl(void)
{
cout << "CRemoteControl构造函数" << endl;
}
private:
};
#define g_remoteControl CRemoteControl::GetInstance()