Core Java - static data member

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static data member

what is the use of static data member?

Total Answers and Comments: 4

Last Update: August 04, 2008 Asked by: amitjhjsr

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July 12, 2008 22:52:08

r.praveenkumar

Member Since: October 2007 Contribution: 24

RE: static data member

consider a situation where we would like to count the no of objects created for a particular class. let us consider a program

class ex
{
public int count;
public ex()
{
count=count+1;
}
public static void main(String as[])
{
ex o1,o2;
System.out.println(o1.count);
System.out.println(o2.count);
}
}
the output is
1
2

in the first line see 1 is the output though 2 objects are created this is because
o1.count is different from o2.count these two counts are totally different from each other so to maintain a data member which is common to all the objects we go for static data member.

now consider the following program which counts exactly the no of objects created.

class ex
{
public static int count;
public ex()
{
count=count+1;
}
public static void main(String as[])
{
ex o1,o2;
System.out.println(o1.count);
System.out.println(o2.count);
}
}
the output is
2
2

see now we got the correct output here the static count is common to all the objects if we change the value in one it will automatically reflect in all objects.

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July 13, 2008 02:48:42

chanty

Member Since: May 2008 Contribution: 1

RE: static data member

static data member are those which do not take different memory every time when we call the object hoe many times it may be.ex

class sample
{
static int a;
increment()
{
a++;
}
system.out.println(" amar.509@gmail.com ");
}

class mainc
{
public static void main(string args[])
{
sample s=new sample();
sample s1=new sample();
sample s2=new sample();
s.increment();
s1.increment();
s2.increment();
}
}

Actually in the above progarm when we cal increment() variable "a" is to be incremented for a particular object only.
But when we cal increment() with s1 and s2 the value of "a countinus to increment"

{for each object the variable which is static should not take different memory locations and it will countinue in the same memory location}

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July 28, 2008 03:39:57

sudampanigrahy

Member Since: July 2008 Contribution: 5

Static data member

PROPERTYS OF static KEYWORD:

The datamembers declared with static keyword is is treated as Constants, those values cannot be changed throughout the program...

As well for the static data members the memory is allocate in the seprate area called as "context" area.
static datamemebrs are accessable without declering objects
they can be accessable with the class name

eg: Student.roll_no;

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August 04, 2008 10:28:21

naresh5m

Member Since: July 2008 Contribution: 1

RE: static data member

Static Data Member has an intersting feature for the programming languages.

1) While creating functions (2 Reduce the fode redundance) the results of that funcing will have to return to use out side of the function. If cant return that value then we dont have have a change to use the out put of the function. if we store in the static variable then it will be accessed thrught the program.

2) The properties of one class is copied for all the function of the same/another class, no need to reprasent the same thing in no. of time. Just declare it as static then it solves the probelm.

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