Help with a question from JCHQ

[srini bhav]

Hi ,
I just came across a question in JCHQ.
What will happen when you attempt to compile and run this code?
public class MySwitch{
public static void main(String argv[]){
MySwitch ms= new MySwitch();
ms.amethod();
}
public void amethod(){
char k=10;
switch(k){
default:
System.out.println("This is the default output");
break;
case 10:
System.out.println("ten");
break;
case 20:
System.out.println("twenty");
break;
}
}
}
1) None of these options
2) Compile time errror target of switch must be an integral type
3) Compile and run with output "This is the default output"
4) Compile and run with output "ten"
The answer was 4.
I can understand it but will it not cause a problem when the variable k is being assigned with a value not enclosed in single quotes ?
I was thinking that the answer might be 3 because of that.
Can someone please explain ?
Thanks,
Srini

[Manfred Leonhardt]

Hi Srini,
An integer literal used in an assignment statement is handled by the JVM. It will be allowed unless the size of the literal will not fit into the new variable type.
int i = 16; // Works
short s = 16; // Works
byte b = 16; // Works
char c = 16; // Works
short s = 1000; // Won't work
byte b = 259; // Won't work
short s = 13465; // Won't work
char c = -194; // Won't work (char is unsigned!)
Regards,
Manfred.

[lee dalais]

hi srini
if u enclose a char literal with single quotes, the compiler requires a letter or unicode sequence after the first quote, so
char k='10' gives compile error.
hope that helps

[srini bhav]

Thanks guys for helping me out and Lee, thanks for that concept. I never knew it .
Srini

[lee dalais]

hi srini
u should check out the java language specification for really good insite to the language.
http://java.sun.com/docs/books/jls/second_edition/html/j.title.doc.html