please explain which output is right?

[Sonali Sehgal]

    
public class TestClass3
{
   public void loopTest(int x)
   {
      loop: for (int i = 1; i < 5; i++)
      {
         for (int j = 1; j < 5; j++)
         {
		System.out.print(i);
            if (x == 0) {  continue loop;  }//1
            System.out.print(j);//2
         }
      }
   }
	public static void main(String[] args) {

	TestClass3 t=new TestClass3();
	t.loopTest(0);
	}
}

This question is from enthuware.If we execute this program it gives the output 1,2,3,4 and if we comment the line (1) then it gives a different output as 11121314212223243132333441424344...

My question is the above output must be at one time when line is not commented...
Why does program in output 1234 does not print j it only prints i.It never reaches line 2 ...This is what I dont understand why??

[S. Vijay]

In the above code we have "continue loop" right that is the reason we get 1,2,3,4. I will explain how it is so.

Here loop is a label. Initially when the control comes to first for loop (i.e i for loop here in our case) it has the i value as 1 and then it enters into the j for loop then it prints the i value i.e 1 to the console and then comes to the if statement here x equals 0 condition gets satisfied and hence continue loop statement gets executed. Now the tricky thing happens, the control immediately jumps out of the j for loop and then goes back to the label loop: part and then it increments the i value to 2 now and then checks the condition whether it is lesser than 5 or not and if so it enters into the j for loop again and now this time it prints 2 to the console and in the same fashion the rest of the output 3,4 is displayed on the console.

If we comment line 1 then the control comes to j print statements also and hence j values will also get printed.

I hope my explanation made you clear if not feel free to ask

Regards
Vijay

[Sonali Sehgal]

Hi Mr. Vijay,

the line does not ever reach line 2 I mean this is what I dont understand why does it not reach line 2...as far the brackets of IF statement is concerned it also is closed prior to that..still it does not reach line 1 I mean why???

[S. Vijay]

You try to go through working of continue.

Yes the control does not reach line 2 because of the contine statement. Always the value of x is 0 and the condition gets satisfied every time and on encountering continue loop it jumps out of the j loop before printing the j value and the control comes to the i for loop. Does my explanation clear your doubt?

[Sonali Sehgal]

Hi Vijay,

Thanks I think now I understand it now....

[Mo Jay]

Hi,

I think Sonali needs to do some reading about continue and break in a loop and what each of them does then you will figure out why line 2 was never reached.
Note that x=0 has never changed in your code and there is no modification or increment for this value thus condition is always true and continue is always executed.

Cheers!!!

[Ninad Kulkarni]

@Sonali
See JLS for continue operation