labelled break

[Cameron Park]

Hi, I have a question about labelled break.
mainloop: for(int i = 0; i < array.length; i++){
for(int j = 0; j < array[i].length; j++){
if(array[i].secondArray[j]=='\u0000'){
break mainlooop;
}
}
}
does the flow of the program leaves the "j for loop" and go to the "i for loop" with i incremented? If that is the case, what's the difference between a labelled continue and a labelled break?

mainloop: for(int i = 0; i < array.length; i++){
for(int j = 0; j < array[i].length; j++){
if(array[i].secondArray[j]=='\u0000'){
continue mainlooop;
}
}
}

[Anonymous]

A break with a label breaks the entire loop. So it breaks out of the i and j loop. continue label; begins in the mainloop again:

public class LabeledLoop{

  public static void main( String args[] ){
    int myArray[] = new int[ 20 ];
    mainloop:
    for(int i = 0; i < myArray.length; i++){
      for(int j = 0; j < myArray.length; j++){
if( j == 5 ){
  System.out.println( "breaking" );
    break mainloop; // Using break here makes the two for loop stop executing
    //continue mainloop; using continue here makes the i for 
//loop starts with his next increment. so if i was 3 
//before it starts with 4 this time
}
System.out.println( "j: " + j + " i: " + i );
     }
   }
 }
}

[This message has been edited by Mathias P.W Nilsson (edited August 18, 2001).]

[Cameron Park]

Then do it starts with i==0, all over again? Or just ++i like continue?

[Cameron Park]

Hi, I really need to know this. Somebody please help?

[INDU, BALA]

Hi Cameron,
Just I have changed Nilsson's code little bit and executed,
go thru this code and its output
code 1:

public class LabeledLoop{
  public static void main( String args[] ){
           int myArray[] = new int[ 3 ];    
           mainloop:    
           for(int i = 0; i < myArray.length; i++){
           for(int j = 0; j < myArray.length; j++){
           if( j == 2 ){
           System.out.println( "breaking  mainloop" );
           break mainloop; }
           System.out.println( "j: " + j + " i: " + i );    
           }   
           } 
           }
}

The output is
j: 0 i: 0
j: 1 i: 0
breaking mainloop

If you replace break mainloop with continue mainloop the output will be like this
j: 0 i: 0
j: 1 i: 0
continuing mainloop
j: 0 i: 1
j: 1 i: 1
continuing mainloop
j: 0 i: 2
j: 1 i: 2
continuing mainloop

Hope this helps
Indu

[Ernest Lee]

break label works like this:
here:
for (;
for (;
break here; //line A
//line B
when program reach line A, it will first go to "here: " and then go the line B.. (skip things in between). Try to put "continue here;" instead of "break here;" and u will enter an infinite loop! haha