What is singleton design pattern
- 1 Answers
- 9559 Views
- CSS, Dimdim, Fulcrum Logic, TCS, Wipro, I also Faced
- E-Mail Answers
Answer Posted / lokesh
Singleton design pattern is a a creational pattern to
dictate how and when objects get created and it's main
purpose is to ensure that a class has only one instance
Example:
#define NULL 0
class Singleton
{
private:
Singleton(Singleton&){}
Singleton& operator =(Singleton&);
int nValue;
static Singleton* pSingleton;
Singleton():nValue(10)
{
}
public:
static Singleton*Instance()
{
if(NULL == pSingleton)
{
pSingleton = new Singleton();
}
return pSingleton;
}
void setValue(int val)
{
nValue = val;
}
int getValue()
{
return nValue;
}
};
Singleton* Singleton::pSingleton = NULL;
int main(int argc, char* argv[])
{
Singleton *abc = NULL;
cout<<Singleton::Instance()->getValue()<<endl;
Singleton::Instance()->setValue(20);
Singleton *xyz = NULL;
cout<<xyz->Instance()->getValue()<<endl;
Singleton *sss = Singleton::Instance();
return 0;
}
| Is This Answer Correct ? | 16 Yes | 5 No |
Post New Answer View All Answers
Are you using singleton in your code?
Can we have this pattern implemented using static class?
What are the differences between the design patterns and the framework?
What is onion architecture?
Give me example of observer design pattern?
Why is singleton bad?
What are the 23 design patterns?
How did you design your unit tests?What about integration tests?
What is a behavioral design pattern?
What is factory method in design pattern?
What are creational design patterns?
What is lexi design pattern?
What is the singleton design pattern?
What is the difference between factory and builder design pattern?
Why is singleton used?
