on constructor

[velan vel]

hai ranchers
why this code is giving compile time error
can any one explain


Q43.What will be the result of compiling and running the given program?
Select one correct answer.

1. class Q43
2. {
3. int y=1;
4. Q43()
5. {
6. this(y);
7. }
8. Q43(int x)
9. {
10. y=x++ + ++x;
11. }
12. public static void main(String [] args)
13. {
14. Q43 t = new Q43();
15. System.out.println(t.y);
16. }
17. }
a Program compiles correctly and prints 1 when executed.
b Program compiles correctly and prints 4 when executed.
c Compile time error.
d None of above.

by
velan vel

[Karu Raj]

Hi

The code doesnot compile because the key word "this" cannot refer to any instance variable but can refer to static variables.

I had the change the code below at //////1 now it works fine and prints 4

Also remember that both this and super keyword cannot have instance variable as arguments but can have static variables.

class Q43 
 { 
 static int y=1; ////////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);
 } 
 }
 

[Harshil Mehta]

Hi velan,

same type of question has already been asked.
see this:
https://coderanch.com/t/252273/java-programmer-SCJP/certification/Superclass-Reference

i think you and Mithran Perry are on the same page.

regards,
Harshil