Boolean Operator

[sandhi mridul]

Hi,

What is the diffrence between "!=" and "=!" operartor.
As per me this operartor can only be applied on boolean first of all.
Also if

b1 != b2; //line 1
here , its doing comparison between b1 and b2.
If they are not equal to each other then line 1 return true otherwise false.

b1 =! b2; // line 2
Here its doing assignment b2 to b1.
That is if b2 is "false" then due to (!b2) true is going to get assign to b1.

Am I right?

***************************************************************************

One more thing I want to ask-

boolean b1=false;
boolean b2=false;

b2!=b1!=b2; //Line 1
b2!=b1=!b2; //Line 2

Are these 2 lines going to compile and run?
For me its giving error stating "Invalid statement".
Also I am confused.
Please help me out with the above two.

Thanks
[ March 09, 2008: Message edited by: sandhi mridul ]

[ahmed yehia]

What is the diffrence between "!=" and "=!" operartor.

The second is not an operator but rather two operators '=' and '!'.
For better readability try: b1 = !b2;

[Hamsagayathri Palanisamy]

Originally posted by sandhi mridul:
Hi,

What is the diffrence between "!=" and "=!" operartor.
As per me this operartor can only be applied on boolean first of all.
Also if

b1 != b2; //line 1
here , its doing comparison between b1 and b2.
If they are not equal to each other then line 1 return true otherwise false.

b1 =! b2; // line 2
Here its doing assignment b2 to b1.
That is if b2 is "false" then due to (!b2) true is going to get assign to b1.

Am I right?

***************************************************************************

One more thing I want to ask-

boolean b1=false;
boolean b2=false;

b2!=b1!=b2; //Line 1
b2!=b1=!b2; //Line 2

Are these 2 lines going to compile and run?
For me its giving error stating "Invalid statement".
Also I am confused.
Please help me out with the above two.

Thanks

[ March 09, 2008: Message edited by: sandhi mridul ]

Hi Sandhi,
what you said is rite.

b1 != b2;

is comparision and

b1 =! b2;

is Assigment
Instead of this

b2!=b1=!b2;

you can use as

      boolean b1 = true;
      boolean b2 = false;
      boolean b3 = b1 =! b2;
      if(b2 != b3)
       //code
      

moreover,i dont know why the following check needed

b2!=b1!=b2;

its enough to have as

      if(b1 != b2)
     or 
      if(b2 != b1)

you may try down as

      boolean b1 = true;
      boolean b2 = false;
      boolean b3 = b1=!b2;
      if(b1 != b2 != b3)
       //code
 

[sandhi mridul]

Thanks Hamsagayathri.
But still not sure if line 1 and 2 going to compile or not.
I found these in 2 diffrent mock test with diffrent answers.
I tried but giving Compiler error.
So just need to conform.

boolean b1=false;
boolean b2=false;

b2!=b1!=b2; //Line 1
b2!=b1=!b2; //Line 2