int a =5; int x = ++a + ++a + ++a;

Question

Need explanation why it comes 22 in output when we print in C language

Answer 1

well, the sum needs two operand, so ++a + ++a increments a twice
a = 5
++a + ++a = 14
then ++a = 8 so
++a + ++a + ++a = 14+8

Answer 2

As I have said, multiple prefix/postfix operators applied to a variable between to sequence points will result in undefined behaviour. The result is completely compiler dependent.

Also, stop using Turbo C++.

https://www.sololearn.com/Discuss/288609/?ref=app

Answer 3

@sayan chandra

It means that when you use multiple prefix, or postfix operators on a single variable between two sequence points (usually two semicolons), it is up to the compiler to determine which operator is performed first. This results in different values for different compilers, and hence undefined.

Answer 4

Please refer:

https://stackoverflow.com/questions/4176328/undefined-behavior-and-sequence-points

Answer 5

The sole fact that Andres got 22 and sayan got 24 has already proven my point.

Please refer, and do some research:

https://stackoverflow.com/questions/4176328/undefined-behavior-and-sequence-points

Your results are compiler dependent.

Answer 6

woah sololearn didn't let me post the answer

Answer 7

https://code.sololearn.com/c3VK6m46RPPy/?ref=app

Answer 8

yep, I was trying to answer before but i couldn't post anything :p

Answer 9

IT'S NOT UNDEFINED BEHAVIOR

Answer 10

exactly what i am saying....andré##✌✌

Answer 11

@sayan chandra as far as i know for arithmetic operations the compiler operatea two variable with a operand at a time not 3 at once...

Answer 12

ya ...i know....but see i am generalising the idea
if u have a=5
and doing ++a adding n times
the reselt is
..(a+n)*n

Answer 13

I'm using code blocks 16.01 with gcc gnu compiler

Answer 14

HERE IS THE LEGIT EXPLAINATION...

there is 3 (++a)

so first c compiler wont do the sum...
it will first determine what is the last incremented value of a...
3 increment..
value is (5+1+1+1)...i.e. 8
now it will calculate ...like 8+8+8= 24

trust me...i ran the code...

and similarly if u do...
++a + ++a + ++a + ++a(4 times)

ans is 9+9+9+9= 36

last incremented value is 9

Answer 15

yes the logic is perfectly right...
because when you do pre decrement..
just like this...

--a + --a + --a
the last decremented value is..
5-1-1-1 = 2
so ans is 2+2+2 = 6
right on my laptop screen..

Answer 16

and the most importent thing is...
in c language code...its not written whether to do all increment (3 times) at once then sum up or another process...(particularly for one program)
like one increment then sum then again increment then sum...(particularly for this program)

so if you have 4 compilers in c they may have different approach####like what to do in such program...how to compute and what to compute next..

and again updates wont change logic...

Answer 17

the language c is fixed...
compilers can be mordern...
its totally okay to avoid turbo c++
but that does not make the logic wrong...

Answer 18

which compiler u r using...
it seems u getting 22...

Answer 19

ooh andré got 22 also....

but please tell me the compiler.
cause in here its 24

Answer 20

rei...wil you please shorten the meaning of that link..
i mean just tell what is the breif idea..
the page is large...
is it...compiler varies...calculation varies
???