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Do while loop syntax in java

Posted on 2008-10-10
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Last Modified: 2013-12-14
I have some java code for a simple do while loop but it is exhibiting some strange behavior. Sometimes it works but sometimes it exits the loop when it is not supposed to. Can anyone see what I'm doing wrong with this?

I have checked that I am receiving keyboard input correctly and setting the flag to 4 when entered.
I have just put the relevant code.

Thank you
int flag = 0;
do
{
  if (flag == 4)
  {
  System.out.print("Quitting");						
  }
}
while(flag != 4);

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Question by:GrimReeper
7 Comments
 
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by:
Ajay-Singh earned 167 total points
ID: 22685484
Its infinite loop for any value other than 4. What is that you want to achieve with this loop?
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Assisted Solution

by:petr_hlucin
petr_hlucin earned 167 total points
ID: 22685491
I suppose that value of flag is modified in a different thread. Make sure modyfying of this value takes place within a critical section.
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Author Comment

by:GrimReeper
ID: 22685494
I want the loop to keep running until input is changed to 4 but the loop exits when input is 1.
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LVL 2

Assisted Solution

by:Monky42
Monky42 earned 166 total points
ID: 22685573
You need to provide more information. If you are using multiple threads please post all code concerning the two threads and the synchronized flag value. If you are not using multiple threads you might have a design problem. The loop as you have posted it is senseless.
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Author Comment

by:GrimReeper
ID: 22685590
I have changed it to a while loop and now it works. Strange but thanks for the help anyway.
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Author Closing Comment

by:GrimReeper
ID: 31504943
Thank you
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Author Comment

by:GrimReeper
ID: 22685660
For anyone interested it ended up being the validation from another class I had was kicking in. I always forget the most simple of things that have the biggest consequences haha.
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