Variables[code]

class A10{ public static void main(String args[]){ byte b1=10; char ch1=b1; final byte b2=10; char ch2=b2; }

what is the reason for;
4th line's compilation error & 6th line compile perfectly???

hi kamani,

"In java constant and final expressions are evaluated at compile time, however variable expressions are evaluated at run time".

In your code b2 is final i.e. compiler knows that its value is with in the range of char(0-65535) and that why line 6 wont cause any
problem.

Now, lets talk about byte b1=10; char ch1=b1;
Its a variable expression(line 02.), and will be evaluated at run time, thats why compiler is not aware of this fact that b1 is also with in the
range of char. However it(compiler) just know one thing that b1 is byte, and that why gives compile time error as byte consist of
negative range also(-1 to -128) that can not be assigned to chars...

I hope you get my point...

thanks a lot.

class Q{ public static void main(String args[]){ double d1=3/2; double d2=3/2d; double d3=3/2f; System.out.print(d1+" "+d2+" "+d3); } }

what is the reason for getting result as "1.0 1.5 1.5"
d1 also a double and it assign to 3/2

The division is still an integer division, without decimal part. 3/2 is always 1. Assigning that 1 to a double doesn't turn it into 1.5.

swaraj gupta wrote: . . . "In java constant and final expressions are evaluated at compile time, however variable expressions are evaluated at run time".

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