Why in Java result = 8, but in C result = 9

Question

https://code.sololearn.com/c8y6W18Vlw1A/?ref=app
https://code.sololearn.com/c05gmsGROhPU/?ref=app

Answer 1

Precedence and associativity of postfix ++ and prefix ++ are different;

 ➝ Precedence of postfix ++ is more than
prefix ++, their associativity is also different.

Associativity of postfix ++ is left to right
  and
associativity of prefix ++ is right to left.

• https://code.sololearn.com/cZh21tT8Yn4D/?ref=app
• https://code.sololearn.com/ck689G7hHxg9/?ref=app
• https://code.sololearn.com/cdiP8gSPdSTi/?ref=app

Answer 2

UraL The problem is that you're trying to calculate something that cannot be calculated. 9 is one correct result, but it is not THE correct result. If another compiler says that the result is 8, that result is also correct. Same for 7, 10, or whatever other compilers may get as result. EVERYTHING any arbitrary compiler claims to be the correct result is correct because undefined behavior leads to unpredictable, yet formally correct results.

Answer 3

https://www.sololearn.com/Discuss/1838305/?ref=app

Answer 4

UraL (with reference to C) if u want 8 as answer do,
i = i++ + ++i;
I had observed it, just now. Well, I also don't know the answer of your doubt !!!

Answer 5

It's bad practice to have such dubious incrementing in your code which depend on language specific implementations but I agree it's interesting academically.

Answer 6

Anna
Thanks. Very detailed answer:-)

Answer 7

Sonic this question appear with help SoloLearn challenge. In Java I answer 9 (as in C), but there was answer 8

Answer 8

UraL The answer in C isn't 9 though. The answer in C is undefined behavior

Answer 9

UraL
- "The output in C is 9."
- "The output in C depends on the compiler."

Pick one of them, you can't have both

Answer 10

public class Program
{
public static void main(String[] args) {

int i = 3;

i = ++i + i++;

System.out.println(i);
}
}

result = 8

++3 instantly 4

4++ remains 4

4+4 = 8 stored in i

then 4++ value become 5

but in next statement we printing value i

but i is having 8

=================

Answer 11

Sonic it was in SoloLearn

Answer 12

@Anna I think in C is correct

Answer 13

Although all depend on compiler

Answer 14

With or without brackets the result in C is 9

Answer 15

Suzie and what about i++ ?

Answer 16

kamlesh patil thanks

Answer 17

@Anna result is 9, but I can't guarantee it on all C compilers. By my opinion it must be 9 definitely. But I am not compiler designer. So programmer should not use such ambiguous in one line. Otherwise he can spend a lot of time to debug program.

Answer 18

Srinivasa Karthik Java ignore i++.

Answer 19

Cool

Answer 20

UraL Just because the c compiler takes the new value of i i.e. 4 (because of ++i) therefore making i++ = 5. And yielding a result 9.
But java being interpreted takes the same value of i for both i++ and ++i throughout the line, therefore making i 8.