Multiple choice questions..

[carly]

hi,

i've been solving these multiple choice questions, and i'd like to know if what i answered is right ot wrong......... just to double check :)

I) Consider the code given below.

   class Base{} 
    public class MyCast extends Base{ 
        static boolean b1=false; 
        static int i = ‐1; 
        static double d = 10.1; 
        public static void main(String argv[]){ 
             MyCast m = new MyCast(); 
             Base b = new Base(); 
             //………..Here 
    }} 

Which of the following, if inserted at the comment //Here will allow the code to compile and run without error
(a) b=m;
(b) m=b;
(c) d =i;
(d) b1 =i;

- chose (a) because a variable which is declared as a base class can also take instances of subclasses, whereas a variable that's declared as a subclass cannot be set to a superclass.


(II) Given the following variables which of the following lines will compile without error?
String s = "Hello";
long l = 99;
double d = 1.11;
int i = 1;
int j = 0;

(a) j= i <<s;
(b) j= i<<j;
(c) j=i<<d;
(d) j=i<<l;

- I chose (b) because you can't shift by a long, double, or a string.


thanks,

carly :D

[r035198x]

hi,

i've been solving these multiple choice questions, and i'd like to know if what i answered is right ot wrong......... just to double check :)

I) Consider the code given below.

class Base{} 
public class MyCast extends Base{ 
static boolean b1=false; 
static int i = ‐1; 
static double d = 10.1; 
public static void main(String argv[]){ 
MyCast m = new MyCast(); 
Base b = new Base(); 
//………..Here 
}} 

Which of the following, if inserted at the comment //Here will allow the code to compile and run without error
(a) b=m;
(b) m=b;
(c) d =i;
(d) b1 =i;

- chose (a) because a variable which is declared as a base class can also take instances of subclasses, whereas a variable that's declared as a subclass cannot be set to a superclass.


(II) Given the following variables which of the following lines will compile without error?
String s = "Hello";
long l = 99;
double d = 1.11;
int i = 1;
int j = 0;

(a) j= i <<s;
(b) j= i<<j;
(c) j=i<<d;
(d) j=i<<l;

- I chose (b) because you can't shift by a long, double, or a string.


thanks,

carly :D

For the first one, with a 1.5 compiler you also get
d =i; as valid. An integer can be stored in a double reference

For the second one, You can shifta long!