Java += and implicit casting
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java += operator
until today i thought that for example:
is just a shortcut for:
but what if we try this:
then
does it mean that in fact
i've tried googling for it but couldn't find anything relevant.
a good example of this casting is using *= or /=
or
or
or
question
until today i thought that for example:
i += j;is just a shortcut for:
i = i + j;but what if we try this:
int i =5;long j =8;then
i = i + j;
will not compile but
i += j;
will compile fine.
does it mean that in fact
i += j;
is a shortcut for something like this
i = (type of i) (i + j)
?
i've tried googling for it but couldn't find anything relevant.
answers
as always with these questions, the jls holds the answer. in this case §15.26.2 compound assignment operators . an extract:
a compound assignment expression of the form e1 op= e2 is equivalent to e1 = (t)((e1) op (e2)), where t is the type of e1, except that e1 is evaluated only once.
and an example:
for example, the following code is correct:
short x =3; x +=4.6;and results in x having the value 7 because it is equivalent to:
short x =3; x =(short)(x +4.6);
in other words, your assumption is correct.
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a good example of this casting is using *= or /=
byte b =10;
b *=5.7;system.out.println(b);// prints 57or
byte b =100;
b /=2.5;system.out.println(b);// prints 40or
char ch ='0';
ch *=1.1;system.out.println(ch);// prints '4'or
char ch ='a';
ch *=1.5;system.out.println(ch);// prints 'a'
Java (programming language)
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