Char and Ints

[Lalit Goyal]

Can any one explain
public class chchar
{
public static void main(String str)
{
char c='a';
int i =2;
c=c+i;
System.out.println(c);
}
}
gives you an error but
public class chchar
{
public static void main(String str)
{
char c='a';
int i =2;
c+=i;
System.out.println(c);
}
}
Works fine.
What is the diffrence?

[Wong KK]

For c = c + i,
it is doing as c = (int) c + i;
assigning an int to a char is not allowed without explicit cast unless the int is a final
For c += i,
it is doing as c = (char) c + i;
so it is alright.

[Ajay Patel]

The diff is simple
c+=i;
is treated as:
c = (char)(c+i);
Since the result of c+i is an int it requires an explicit cast. In the first code u havent provided this cast so compiler complains. But as u see above in the second case the cast is implied implicitly.
Remember this point. It is very imp for SCJP exam
-Aj

[Sandy Lee]

Its the way the two assignments work:
When you use c += b, behind the scenes, this is what is actually happening (char)(c+b).
So the casting is taken care by JVM for you.
However in the first case, you are adding a char and a byte. This will return an int which who are assigning to a char variable. causing it to complain.
Trust this helps.