Clarify...while....

[Shiaber Shaam]

{
boolean a;
while(a = true)
{}
}

will it work...

[Siri Naray]

No it wont work. = is an assgnment operator not a boolean ope.

[Pinkal Patel]

It will work

while (a=true)

couse
1) var 'a' is boolean type
2) and while(a) using varialve not directly true so no compile time error

[S Thiyanesh]

void m(){
   while(true);
}

This will compile.

But if

void m(){
   while(true);
   System.out.print("Unreachable");
}

If there is any statement after while(true) its unreachable.

[Shiaber Shaam]

Like if(a = true), will while(a = true) work?...............

[Anoop Kavalloor]

The class will compile fine and when u run the class u ll get an infinite loop. The line while(a=true) make the variable a as true. It is equivalent of writing

boolean a = true;
while(a){
}

[Shiaber Shaam]

while(boolean b = true)//1
if(boolean b = true)//2

Above two are correct or not..........

[wise owen]

No. They need expression and not declaration.

[Vladimir Scheglov]

Interesting
This code not compile

while (false){
int i = 5;
}

[joshua antony]

This will not compile because i=5 is never reached

[Vladimir Scheglov]

Hi Joshua
But why this code compile fine?

if (false){
int i = 5;
}

[joshua antony]

Te compiler is not smart enough to identify not reachable code using if.
I think we have to simply remember this.
If there is any logic please let me know.

[Joel Arnold]

I read that there is a rationale for this seemingly inconsistant behavior, it is made this way to allow programmers to have code that runs only while debugging :

for example with the use of a constant DEBUG that will be set to false in production code :

if (DEBUG)
System.out.println("I wouldn't wanna see that in production code...");

Hope this helps !

Cheers !

Joel

[Finner Jones]

Hi guys,
Here's my penny's worth.
Example:

 
while(false) {
  // unreachable code compile time error
}
 
while (a=false) {
  // no error at compile or runtime
}
 

The syntax for while is

while (expression) {
// do something
}

Therefore (a=false) is an expression which is left until runtime
whereas (false) is already known at compile time so there is an error.
Does that make sense ?

Finner

[Swapnil Trivedi]

Originally posted by S Thiyanesh:

[CODE]void m(){
   while(true);
   System.out.print("Unreachable");
}

If there is any statement after while(true) its unreachable.

Hi Thiyanesh..
i just checked it... this code also runs fine because it's while(true) so the statement just after while is always reachable but if it's while(false) then it will give compiler error of saying that the statement below while is unreachable.

code: while(true)
{
System.out.println("Compiles fine");
}

code: while(false)
{
System.out.println("Unreachable statement");
//since at compiletime the statements below while are unreachable
}


Regards
swapnil

[Naseem Khan]

if (false){
  int i = 5;
} 

In if statements, the body of if will be compiled only if compiler can deduce the condition to be true.