dan exam dought 5

[amit taneja]

hi guys
in one question of DAN ...

class Sienna {
static double a; static float b; static int c; static char d;
public static void main(String[] args) {
a = b = c = d = 'a';
System.out.println(a+b+c+d == 4 * 'a');
}}

What is the result of attempting to compile and run the program?

a. Prints: true
b. Prints: false
c. Compile-time error
d. Run-time error
e. None of the above


its answer is "a"

with explanations
The literal, 'a', is promoted to type int; and is then multiplied by the value of the left operand, 4. If one of the two operands of a numeric expression is of type int, then the other operand will be promoted to type int if it is of type short, char or byte.


----------------
the above explanation is true but its only half explantion... !!!

but why "a" and not "b" ??
as in above question... left side of == operator will be changed into double .... and which is not equalant to interger no. on the right hand side...




pls correct my post ...if wrong ...

thanx

[Akash Roy]

Hi,

During == operator implicit widening takes place. Hence the Integer on the right side gets promoted to double.

Regards,

[Carol Enderlin]

Amit,

Did you try compiling and running the code? Playing around with it a little to see what it is doing? (see code below, I added a couple of print statements since I didn't remember what int value 'a' had and wanted to "SEE IT".)

If the == part was confusing, how about this:

1. static double a; static float b; static int c; static char d;
2. a = b = c = d = 'a';

Line 2 assigned a char to a char to an int to a float to a double!

 
class Sienna {
  static double a; static float b; static int c; static char d;
  public static void main(String[] args) {
    a = b = c = d = 'a';
    System.out.println(a+b+c+d == 4 * 'a');
 

    System.out.println('a' + 0);
    System.out.println('b' + 0);
  }
}

[amit taneja]

thanx a ton Carol Enderlin

regards