|
A singleton can be used in places where you need an instance, so you can still do all that inheritance/polymorphism/etc with it
A static classes can only derive from Object and can not implement interfaces
|
|
|
|
|
All members inside a static class would be static - and hence not available for automatic garbage collection until the app domain is unloaded.
In the case of a singleton class, the instance variables defined in the class will be available for garbage collection.
So singletons have an advantage with respect to memory de-allocation.
| There are only 10 types of people in this world — those who understand binary, and those who don't. |
|
|
|
|
|
Hi, I think the difference between the two classes is that
Static Class needs no instance of the object,
while Singleton needs one instance of object and to keep the state.
modified 27-May-14 4:59am.
|
|
|
|
|
Hey how to generate orthogonal partitions. I have a rectangle and i wish to divide it into 8 random partitions and load an image into each partition. can anyone tel me how to do it?
|
|
|
|
|
Hi,
maybe like so:
0. create one random number generator; use only one!
1. choose a random number in the range [0, 2) to select direction (0=horizontal, 1=vertical).
2. choose a random number in the range [0, max) where max is either width or height.
3. repeat 1+2 three times.
You now have 8 rectangles inside the original one.
refinements: impose a minimum width and height for each of them by limiting the range in (2) somewhat.
|
|
|
|
|
Hey wont they superimpose??
|
|
|
|
|
Not unless you want them to. Of course, you'd have to be a programmer to bend the application to your will.
.45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001
|
|
|
|
|
when you have three (or N) hor/ver lines inside a rectangle, they cut it in 8 (or 2^N) pieces, no matter what (assuming the lines are all different).
|
|
|
|
|
No they don't!
Rectangle:
+---+
| |
| |
| |
| |
| |
| |
| |
+---+
Add three lines (all different):
+---+
| |
|---|
| |
|---|
| |
|---|
| |
+---+
4 rectangles.
Go back to original and add three other lines (all different)
+---+
| | |
|-+-|
| | |
|-+-|
| | |
| | |
| | |
+-+-+
6 rectangles.
All those who believe in psycho kinesis, raise my hand.
|
|
|
|
|
you're right of course, as your ASCII artwork makes abundantly clear.
So the algorithm needs a fix, something like: add any of {(7,0), (3,1), (1,3), (0,7)} hor/ver lines at random but different locations in the rectangle.
Homework: find all solutions for an arbitrary number of partitions.
|
|
|
|
|
I don't do homework. 
All those who believe in psycho kinesis, raise my hand.
|
|
|
|
|
refinements: disimpose a minimum width and height for each of them by limiting the range in (2) somewhat. everything as litter.
|
|
|
|
|
I am learning C# and OOP, i just cant understand how a static constructor can be useful... can someone please help me with this?? if possible, can u give a simple example? thank you very much...
Marcus Abrahão
Thank you all very much for your help
modified on Wednesday, January 6, 2010 7:12 AM
|
|
|
|
|
mabrahao wrote: static constructor can be useful
No such thing. static is usefull if you call function without intilizing class. If you intilize, constructor is called
public class Test
{
public Test(){}
public static Color GetColor()
{
return Color.White;
}
}
Color c = Test.GetColor();
|
|
|
|
|
Saksida Bojan wrote: mabrahao wrote:
static constructor can be useful
No such thing. static is usefull if you call function without intilizing class. If you intilize, constructor is called
This turns out not to be the case: Static Constructor[^]
All those who believe in psycho kinesis, raise my hand.
|
|
|
|
|
Thats good to know. I didn't even think it was possible
|
|
|
|
|
Ok, static methods and static class was able to figure out how it works, but not the STATIC CONSTRUCTOR, like so:
public class Test
{
int numTest;
// Static Constructor
static Test()
{
numTest = 5;
}
}
i am reading a book from Andrew Troelsen, about C#, and in the book, he gives a example of a static constructor, but i just could not understand...
anyway, thank u for u help
Marcus Abrahão
|
|
|
|
|
Saksida Bojan wrote: No such thing.
What are you talking about? Of course there is. You might find reviewing this[^] useful.
"WPF has many lovers. It's a veritable porn star!" - Josh Smith As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.
My blog | My articles | MoXAML PowerToys | Onyx
|
|
|
|
|
I didn't know it was even possible.
|
|
|
|
|
I wouldn't use the terminology "static constructor" (as ALL constructors are NECESSARILY static - you cannot invoke an instance method until you've constructed an intance). But there certainly is something that (in C#) uses the keyword "static" followed by same syntax as a constructor - the class initializer.
Class initializers can be used if you want to perform initialization of some kind once before a type can be used. For example, let's say you are making a bookmaker system. The prices (odds) may vary from 1.01 to 1000, but not everything in between is legal. Instead you have something like this:
From To Increment
1.01 2.00 0.01
2.02 4.00 0.02
4.04 10.00 0.05
....
500 1000 10
You could use an Int32 to store the integral number of 1/100 units, i.e. 125 for 1.25, and cover more than the range you need. But if there are only 256 legal prices you could store it in just a byte. This could make a big difference when tens of thousands of transactions per hour are to be handled, especially in terms of writing data to a database.
Anyway, it doesn't really matter for our purposes whether or not the representation is useful! The point is this is a good candidate for a type initializer. Given a byte value of 135, we need to find price number 135 of the legal prices. So we can equip the class with an array and initialize the type before it's used like this:
public class OddsPrice
{
static int[] priceArray;
static OddsPrice()
{
priceArray = new int[256];
int price = 100;
int i = 0;
while ((price += 1) <= 200) priceArray[i++] = price;
while ((price += 2) <= 400) priceArray[i++] = price;
...
}
byte value;
public int Value
{
get { return priceArray[value]; }
}
}
The type initializer will be called automatically at an undefined time (in current implementations of the CLR I believe it happens when the assembly is loaded, but the spec says undefined so don't assume anything) prior to the type being used at run-time.
The advantage is that you do not need to handle any thread-syncing to ensure it runs once and only once and before anything else on the type can be used.
|
|
|
|
|
Have a look on MSDN[^]
Hope this helps.
|
|
|
|
|
|
If you have a static class, or there is init for the class which must be done once per application (rather than done once for each instance of the class) then use a static constructor.
See here: Static Constructor[^]
All those who believe in psycho kinesis, raise my hand.
|
|
|
|
|
Thank you, this was helpful
Marcus Abrahão
|
|
|
|
|
Hi,
I have written a complex program in c#.net.
After the program is running for a long time by user interactions, its memory usage will increase to the limit of the system, then error will occur. How can the program alert the user that the memory usage is nearly close to its limit before it goes into error ?
I have tried memory garbage collection but the program is too complex that garbage collection cannot clean up the memory usage effectively.
Thanks
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
