Problem with while statement

[Rohan Deshmkh]

Why this code prints 3 and not enter into an infinite loop?

class TestClass
{
  public static void main(String args[])
  {
    boolean b=false;
    int i=1;
    do
    {
       i++;
    }while(b=!b);
   System.out.println(i);
  }
}

Doesn't the while(b=!b) always evaluates to true irrespective of the value of b?I thought assignment statement as a condition always evaluates to true.

[Henry Wong]

Rohan Deshmkh wrote:Why this code prints 3 and not enter into an infinite loop?

class TestClass
{
  public static void main(String args[])
  {
    boolean b=false;
    int i=1;
    do
    {
       i++;
    }while(b=!b);
   System.out.println(i);
  }
}

Doesn't the while(b=!b) always evaluates to true irrespective of the value of b?I thought assignment statement as a condition always evaluates to true.

And that is where the flaw is ... see section 15.26 of the JLS.

http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.26

specifically ...

At run-time, the result of the assignment expression is the value of the variable after the assignment has occurred.

Henry

[Rohan Deshmkh]

Ok thanks , i got it.