why this with static

[vikky agrawal]

class GFC404 {
private static int x=1;
static void m1(int x, int y) {x++; y++;}
public static void main (String[] args) {
int y=3; m1(x, y);
System.out.println(x + "," + y);
}}

the value of x should be 2 after invocation of method but it shows 1??
static variable are class variables and each instance points to that same variable then why no increment in x???

[Bob Wheeler]

vikky.ag agrawal wrote:
the value of x should be 2 after invocation of method but it shows 1??
static variable are class variables and each instance points to that same variable then why no increment in x???

Hi Vikky,
we have here variables of the primitive data type int. So nothing points to anywhere. Actually for this problem it doesn't matter if we have instance or static variables.
After the call to the method, copies of the variables are creates and these copies are incremented and not the static variable x or the local variable y:

 
class GFC404 {
private static int x=1;
static void m1(int x, int y) {x++; y++;} // after the call, two copies of x and y are created. these copies are incremented
public static void main (String[] args) {
int y=3; m1(x, y);
System.out.println(x + "," + y); // here the original variables are accessed: x=1 and y=3
}} 
   

[Kieren Dixon]

Pass by reference VS Pass by value

[wei luo]

Hi, man,

if you look at the code, the m1 method is not increasing the "private static int" x at all!!!
m1 is merely increasing a copy of one of the parameters that is passed to it.
The question is set up in this way to fool us, actually, the following code behaves the same way as your original code:

  class GFC404 { 
private static int x=1; 
static void m1(int foo, int y) {foo++; y++;} // replace x with foo, and your life is much better
public static void main (String[] args) { 
int y=3; m1(x, y); 
System.out.println(x + "," + y);   // prints the "private static int" x, so nothing is changed, it remains 1
}}   

[Brian Legg]

Please site your sources when posting code

[vikky agrawal]

Bob Wheeler wrote:

vikky.ag agrawal wrote:
the value of x should be 2 after invocation of method but it shows 1??
static variable are class variables and each instance points to that same variable then why no increment in x???

Hi Vikky,
we have here variables of the primitive data type int. So nothing points to anywhere. Actually for this problem it doesn't matter if we have instance or static variables.
After the call to the method, copies of the variables are creates and these copies are incremented and not the static variable x or the local variable y:

yeah i got the idea actually i was confused...
thanks for your efforts..

[Bob Wheeler]

vikky.ag agrawal wrote:

Bob Wheeler wrote:
yeah i got the idea actually i was confused...
thanks for your efforts..

You are welcome. But PLEASE site your source. Otherwise this post will be deleted, I guess. And other people won't benefit from my superior answer
cheers
Bob