DanChisholm question

[Chandra Bhatt]

Question 14
 
class JMM126 {
  static int i;
  public static void main(String args[]) {
    for (i=1; i<3; i++)     {System.out.print(i);} // 1
    for (int i=1; i<3; i++) {System.out.print(i);} // 2
    int i;                                         // 3
    for (int i=0; i<2; i++) {System.out.print(i);} // 4
    System.out.print(JMM126.i);
}}
 

At line 4 compiler error is there. I thought Line 4 print statement's i is of local scope of for loop, not method variable that is not initialized.
Please focus on this issue.

Source: Dan Chisholm Chapter 8


Regards,
cmbhatt
[ April 08, 2007: Message edited by: Chandra Bhatt ]

[Keith Lynn]

This is from the Java Language Specification 14.4.2.

The scope of a local variable declaration in a block (�14.4.2) is the rest of the block in which the declaration appears, starting with its own initializer (�14.4) and including any further declarators to the right in the local variable declaration statement.

The name of a local variable v may not be redeclared as a local variable of the directly enclosing method, constructor or initializer block within the scope of v, or a compile-time error occurs.

Scope of Local Variable Declarations

[Vishal K Patel]

here,

int i;
is declared in the main() method.
So its a local variable.
and you are trying to create another local variable in for() loop block.
but its a local to the main() method also.

And that is of course not allowed....!!!
That's why the compiler is complaining.
[ April 08, 2007: Message edited by: Vishal K Patel ]

[Chandra Bhatt]

Thanks Keith,

The name of a local variable v may not be redeclared as a local variable of the directly enclosing method, constructor or initializer block within the scope of v, or a compile-time error occurs.

Could you please give me an example of this kind of compiler error and specially done bold.


Thanks,
cmbhatt

[Keith Lynn]

Here is an example of what you can't do.

import java.util.Comparator;
 
public class Test {
 
   public Test() {
      int num;
 
      while (3 < 4) {
         int num = 0;
      }
   }
 
   {
      int num;
 
      for (int num=0; ;) ;
   }
 
   public void print() {
      int num;
 
      if (3 != 3) {
         int num = 0;
      }
   }
 
}

[ April 08, 2007: Message edited by: Keith Lynn ]

[Chandra Bhatt]

Thanks Keith,


Nice refreshment!



Regards,
cmbhatt