Litteral Conversion Auto Cast

[Rafi Fareen]

hi guys,

anyone can explain that:

 

byte c = 27; 

i don't need to put caste for the above, because the compiler does that for me.

what about here ...

 

byte b = 10; 
byte c = b+c;  //i know that b+c will evaluate to integer (default behavior) .. 

by why do i get compiler error when i assign b+c to c?
does that mean compiler puts caste automatically/implicitly only for literal assignments, not for expression assignments?

regards,

Rafi

[Shailesh Phatak]

what if the value of c exceeds 127 ?
Thats why compiler give an error during compilation because once it passes the compilation part Runtime cant do anything and this could be the disastrous situation.

[Harpreet Singh janda]

While assiging a value, You don't have to put a cast if the value you are assigning in within the limit of variable like

 byte b = 10;   

But you have to put a cast if limit exceeds the limit

 byte b = 333;    

While eveluating the expresion the outcome of the expression is always auto promoted to wider type of the element being used in the expression.

and byte, short are always promoted to int.

[Abimaran Kugathasan]

Rafi Fareen wrote:hi guys,

anyone can explain that:

 

byte c = 27; 

i don't need to put caste for the above, because the compiler does that for me.

what about here ...

 

byte b = 10; 
byte c = b+c;  //i know that b+c will evaluate to integer (default behavior) .. 

by why do i get compiler error when i assign b+c to c?
does that mean compiler puts caste automatically/implicitly only for literal assignments, not for expression assignments?

regards,

Rafi

This is called as Arithmetic promotion for binary operators....

[Jehaan Butt]

The bedrock here is this - whenever any arithmetic operation involving two different variables is carried out, the answer is always at least an int, even if the two operands are bytes or shorts.

[Mark Moge]

in addition
You can do sth like this

 
byte a = 0;
byte a += 10;  //compiler adds casting byte a = (byte) a + 10; 

but you cannot do

 byte b = a + 10;  //compiler error - incompatible types