Break and continue inside the case statement

[Shiva Mohan]

    
class Doubt {
  public static void main (String args[]) {
    int i = 0, j = 0, k = 0;
    int h;
label1:
    for (h = 0; h < 6; h++) {
label2:
      do { i++; k = h + i + j;
        switch (k) {
          default: break label1;
          case 1: continue label2;
          case 2: break;
          case 3: break label2;
          case 4: continue label2;
          case 5: continue label1;
        }
      } while (++j<5);
    }
    System.out.println(h + "," + i + "," + j);
}}

The output is 241.But I am getting the answer 151.Please help me for the answer 241 since I have spend myself on this problem for 2 days and couldn�t figure out the correct answer.

[wise owen]

Adding some of println statement may help you to understand why.

    
public class Doubt {  
  public static void main (String args[]) {    
    int i = 0, j = 0, k = 0;    
    int h;
 
    label1:    
      for (h = 0; h < 6; h++) {
System.out.println("h="+h + " --- for()");
label2:
          do { 
    i++; 
            k = h + i + j;
    System.out.println("h=" + h + " i=" + i + " j=" + j +" k=" +k + "---do()");
    switch (k) {          
      default:
System.out.println("default -- break \"for\" loop");
break label1;
              case 1: 
System.out.println("case 1 -- continue then while(++j<5) will run");
continue label2;
      case 2: 
System.out.println("case 2 -- break \"do-while\" loop");
break;
              case 3: 
System.out.println("case 3 -- break \"do-while\" loop");
break label2;
              case 4: 
System.out.println("case 4 -- continue then while(++j<5) will run");
continue label2;
              case 5: 
System.out.println("case 5 -- continue \"for\" loop");
continue label1;
    }
          } while (++j<5);
      }
      System.out.println(h + "," + i + "," + j);
  }
}

[ September 22, 2006: Message edited by: wise owen ]

[Joshua Antony]

hi Shiva,


FIRST ITERATION:

h=0:

i=1
j=0;
k=h+i+j
=1


So switch(1) which results in calling of case 1:
continue label2 - will result in execution of while condition again NOT the do one
so ++j means j=1;

Then the do condition...
i=2
k=h+i+j
= 0+2+1
=3.

now case 3:
break label2; -- break out of the while loop and to the next iteration of for loop.


Second Iteration:

h=1... I think you should figure out from here what happens.

Hope this will help.
Regards,
Joshua

[Shiva Mohan]

I have figured out where I was going wrong and this time of my hand calculation got the correct answer with the help of wise and Joshua. Thank you very much. I wouldn�t have figured it out without your help. Thanks again for your time. Great work.

[Burkhard Hassel]

Hi Shiva,

I think I can guess where your frown came from.

These labels can be tricky, especially in a do-while loop.
Where does the "continue" jump in this example?

int i=0;
label:
do{
if (i==2)
continue label;
System.out.print(i);
}while(++i<4);
System.out.println("READY");

It's tempting to say: "Well, it jumps to the label, and the next line is do, followed by if (i==2)."
But that's wrong.
The continue jumps to the while and the i is incremented.
If it wouldn't, the example would be an endless loop. But it isn't, it will print out

013READY


In the example the same would happen if you said continue; (without label).



Yours,

Bu.