Win a copy of Functional Reactive Programming this week in the Other Languages forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

Constructors r behaving Strangley

 
Hussain
Ranch Hand
Posts: 110
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
hi all,
folllowing program is not compiling whyy??? help me!
class Q43 extends Object
{
int y=1;
Q43()
{
this(y);
}
Q43(int x)
{
y=x++ + ++x;
}
public static void main(String [] args)
{
Q43 t = new Q43();
System.out.println(t.y);
}
}
------------------
Muhammad Hussain
 
Maulin Vasavada
Ranch Hand
Posts: 1873
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Muhammad,
The code is not working because,
when you call this(y) from the no-arg const. at that time variable 'y' is not yet initialized according to the initialization mechanism. here first the constructors are started for execution and at the first step of that all the instance vars you declared are initialized but here we are calling another constructor and so it gets higher priority and gets called w/o 'y' is being yet initialized to value 1.
so it is similar situation like using a variable w/o initializing it which java doesn't allow. if we want to make sure that this is the reason then make 'y' var as static. then it works because static has higher priority in initialization and so 'y' gets initiazlied before we try to use it in the constructor!!

regards
maulin
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic