help for loop variation

[vignesh Ramanathan]

hi all.
i have a doubt
for(int i=0,System.out.println("sometext");i<6;i++){---for body--}
gives the compile time error, but
int i;
for(i=0,System.out.println("sometext");i<6;i++){--for body--}
works fine.. why?.

[Sebastian Janisch]

Look at this piece of code

for(int i = 0, j = 6; i < 10; i++) {
			
		}

works fine, even though it does not say int j.

This is because the kind compiler uses the int declaration at the beginning of every initialization within the for statement.

Since System.out.println cannot be assigned as an int, the compiler complains.

[vignesh Ramanathan]

Thank you sir. i understood it clearly.

[Nigel Shrin]

Sebastian Janisch wrote:Look at this piece of code

for(int i = 0, j = 6; i < 10; i++) {
			
		}

works fine, even though it does not say int j.

This is because the kind compiler uses the int declaration at the beginning of every initialization within the for statement.

Since System.out.println cannot be assigned as an int, the compiler complains.

Hi
Just seen your post and read something relevant. In KB SCJP6 p346, it says you can have multiple declarations in a for loop,
but they must all be the same variable TYPE. This explains why putting INT only once worked for j also.

The string output works ok in this example also in the book:

  public class ForLoopStringInsteadOfIterator {
	public static void main (String[] args){
		int b = 3;
		for (int a = 1; b!= 1; System.out.println("iterate")){
			b = b - a;
		}
	}
}
  

However this introduces a NEW QUESTION:
On rules roundup there is a question that you cannot declare one variable in the loop and one above it, either do both above it, or both within it - you can't mix it up. In this example it is mixed. Has this rule changed - or maybe I did not understand it corrrectly in the roundup?

Thanks

[Harsh Pensi]

Nigel Shrin wrote:

  
int b = 3;   
        for (int a = 1; b!= 1; System.out.println("iterate")){   
            b = b - a;   
        }   
  

In this example it is mixed.

It is not a mixed declaration. b!=1 is not in the declaration part of the for loop.
Following would be a mixed declaration and give compiler error because you are declaring b again in for loop.

  
int b = 3;   
        for (int a = 1, b = 5; b!= 1; System.out.println("iterate")){   
            b = b - a;   
        }   
  

[Nigel Shrin]

Hi Harsh, thanks for explaining that
Nigel